Craftsman tractor w/ 17hp Kohler stalling out

moeballMay 21, 2009

Tractor was running great, I had done a full tune up about 6 weeks ago. Last week, it stalled while I was about 1 hour into mowing, and would not restart (it does crank). I noticed that the clear plastic fuel filter was empty, yet the tank was half full. It was getting dark, so I just pushed it into the garage. A couple of days ago, I started it and it fired right up. I let it run for a few minutes and then shut it off.

Tonight, it started right up again. However, after about 5 minutes, it stalled and wouldn't refire. Again, I saw the filter was empty (it wasn't when I started it). I pulled off the fuel line at the carb, after the filter, and fuel came rushing out. I then pulled the carb off and noticed that the bowl was full of fuel. I pulled the fuel shutoff solenoid and tested the plunger which retracts as it should. I plan to clean out the carb, but have I missed anything? Thanks for any help.

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It sounds as tho you are getting fuel. They don't always put a lot of fuel in the filter. Is the fuel cap vented? Is your engine equipped with a fuel pump? (rear mounted fuel tank?) Fuel pump check valves can cause this condition- but you seem to have fuel in the carb. Or is there some water? Worth a look... If it won't run w/ carb spray - then ignition module maybe suspect.

    Bookmark   May 22, 2009 at 1:26AM
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No, there is no fuel pump. The line goes straight from the tank, to the in-line filter, to the carb. I'm not sure if the fuel cap is vented - but I think it would have to be or how else would the gas go down. I'll try draining the tank and watch how it comes out...

    Bookmark   May 22, 2009 at 7:40AM
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I have the identical problem with my Kohler 17 HP Pro model CV490S. This machine is 5-6 years old. The problem started last summer and continued with its first use this spring.

I have done the following:
1) Replaced the fuel filter with a Kohler filter
2) Cleaned the gas cap vent hole
3) Removed and verified that the fuel line is clear
4) I was getting a puff of smoke after the tractor sat for more than a day and found that gas was bypassing something and mixing with the oil. I changed the oil and installed an in-line fuel shut-off valve. This solved the puff of smoke problem. I don't recall if I did this before or after the stalling problem began.
5) Removed the fuel shut-off solenoid and the carb. bowl. There was gas in the bowl but no debris.

When I turn the key to the first position, I can hear the fuel shut-off solenoid click. I assume that means it's openning to let the fuel flow. Tomorrows test is to remove the in-line fuel shut-off valve and see how long it runs. If that's not the problem, I'll remove the fuel filter and see how long it runs.

I have noticed that the solenoid is extremely hot after the engine stalls.

Is it possible that one of the safety switches(seat, mowing deck) is causing this?

I was ready to replace the solenoid until I found out it's cost is $80-$90. I want to be a little more confident that the solenoid is the problem.

tomplum mentioned water in the carb.. That's curious because immediately after it stalled recently, I took the air filter off and looked down into the carb. and saw a mist hovering and a liquid. I dipped my finger into the liquid and took a wiff. I expected a strong gasoline smell but it wasn't that strong. I never thought about it again until tomplum mentioned it. Is it possible that water/moisture could get in there?

Also, tomplum suggested that it may be the ignition module. Is there a test for that?

All suggestions are appreciated. By the time I've finished cutting the grass, which now takes several days due to the stalling, it's time to start all over again. Life is too short to spend it cutting grass.

Thank you

    Bookmark   May 23, 2009 at 11:29PM
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Typically if the fuel solenoid works freely and activates- it works. Pull off the rubber tip if your concerned. On a very rare occasion something related to the safety switch side of the switch circuit will drop power and shut the solenoid down. Cover your bases. Know that the fuel system is clean, vented etc. Put in a new spark plug. You can always detach the small terminal from the coil , clean the fins of debris,reinstall the shrouding so it cools properly and you verify that way that nothing is trying to shut the coil down. But yes, these modules fail often enough- whether they lose spark completely or fire erratically.
SO what would I do? When it shuts down, take a shot of carb spray and shoot it into the air horn of the carb. If it doesn't want to run- good chance there is not fire at all or when there should be.

    Bookmark   May 23, 2009 at 11:47PM
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tomplum, thank you for reading my post and replying so quickly.

What do you mean by "Pull off the rubber tip if your concerned."

Is there a particular carb. spray that I should use? What wording should I look for on the can.

    Bookmark   May 24, 2009 at 1:00AM
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Mebbe one simple thing got overlooked ? Some Kohler engines are picky about which fuel filter to use. Just make sure you are using the p/n perscribed for your unit.

    Bookmark   May 24, 2009 at 2:21AM
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Thanks rcbe

A couple of years ago I went to a Sears parts warehouse to purchase a fuel filter and I brought the original one with me. They couldn't find the one I wanted and proceeded to tell me that SEars went to one filter that would fit all tractors sold by Sears. I bought it, installed it and the tractor wouldn't run for more than a few minutes. I put the old one back on and it ran fine. I returned the new filter to Sears and told them my story. From my discussion with the parts person, I'm the only person who has ever had that problem.

I went to the local power equipment store and the counter person there said that my situation wasn't impossible but highly unlikely. He was OK with selling me the high priced Kohler fuel filter anyway.

The Kohler fuel filter that I have on there now is about a year old. The engine started acting up a month or two after I installed it. Do they get clogged this soon?

    Bookmark   May 24, 2009 at 9:22AM
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When this kohler engine fuel filter thing crops up, most of the posts refer to two filter types - one type with a finer micron filter rating than the other. If you happen to have the wrong one installed, the fuel supply to the carb is restricted just enuff for the engine to starve for fuel when loaded.

Do they clog quickly? not necessarily - but, during the changeout process, crap can get broken loose from the fuel line inside wall and then possibly clog your filter or get into your carb.
Simplest way to check for such is to take fuel line connection at carb loose - remove spark plug wire - have helper crank engine whilst observing fuel supply rate being pumped into a quart jar or such.. A good stream of fuel usually sez your fuel line/filter/pump are ok - then prob is in carb or ignition.

    Bookmark   May 24, 2009 at 9:41AM
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The trend in marketing today seems to be leaning towards some retailers selling an aftermarket substitute when a customer requests parts. I have noticed too, that some retailers don't even ask first, they just bring the sub part out and begin "ringing it up". AND, if questioned, they will give rose colored reports and testimomy about how they "sell a lot" of these and never had a complaint. Plenty of reasons why they would do that, but not neccessary to get into that detail now. To be somewhat fair, a lot of AM parts will work "adequateley" for a lot of applications. "Fuel filters" IS NOT a category that this always applies to. As mentioned in an above post (and elsewhere), a different "micron rating" of filter media may affect the performance of the engine immediately after installation. To understand why this is true you must realize this: From the moment a fuel filter is placed into service and begins collecting debris, the "micron rating" of the filter media begins to change as well, and the "change" is toward a "smaller" particle rating. As the filter "blocks" particles of debris, the particles begin to form a layer of material covering the media structure. Some of the particles are "angular" with points and corners or spikes on their surface. The angular aspects of these particles "fit into" the spaces of the media and change the size of that space "permanently" Where the space may have formerly allowed a ten micron diameter object to pass, it now will only allow a 2.5 micron diameter object to pass. You might say "Oh goody, now it filters even better than new." Well, it does "filter better" now, but the TOTAL FILTERING AREA has been reduced as the spaces in the filter media fill in and "mat over" from the collected debris. Now, apply this to a "typical" inline fuel filter found on a "typical" OPE engine. In the "pennies for thought" method used in modern manufacturing, the term "minimum" is used quite a bit as in "What is the minimum size fuel filter we can put on this engine, for the minimum cost, that will be satisfactory for the duration of the warranty period?" For the reason of "cost" to the OEM, most of the "factory installed" fuel filters are "tiny little things", with just enough "capacity" (how much it traps before being "clogged") to see it through a couple of years (or even less under certain conditions). The reason the OEM needs it to "last through warranty" is not because the OEM might have to replace a filter "under warranty", it is because a partly clogged, or undersized filter, might cause some other problems (like engine damage from "lean burn") that the OEM WOULD BE liable for "in court". I say "in court", but I mean that two ways. On one hand, a consumer (or a "class" of consumers would likely have to "take them to court" to get satisfaction for any damage incurred from too small a filter (and just imagine trying to convince a judge or jury about how "lean burn" can harm an engine.) On the other hand, the "public court of the consumer vote" would penalize the OEMs (as lost sales) once word got out of how the engines "don't have much power" and they "are prone to galled pistons and burned valves". (Yes, this post sort of rambles on, but it's pouring rain outside so I'm banging on this keyboard instead of getting out of the house.) Anyhow, back to the story. Most of the aftermarket parts manufacturers attempt to make "their copy of the original" LOOK LIKE THE ORIGINAL. They don't always adhere to any "micron rating" specifications that may have been set by the OEM "bid sheet". The AM parts maker only needs to make it "LOOK LIKE" the right filter. Besides possibly using a filter media that catches smaller particles (think "flows less fuel"), they may even provide less filter media inside the filter case (think "flows less fuel"). For the reasons above, I have always replaced the tiny OEM fuel filters on all my OPE engines with a much larger inline fuel filter from an auto parts store. The only considerations are that you select a filter with the correct diameter hose nipples for the size hose your machine has (usually 1/4"). The "over capacity" size of these larger filters more than compensate for a smaller micron rating by offering an exponentially greater filtering area. To quote some of the "parts personnel", "I use them on all my machines and never had a problem."

    Bookmark   May 24, 2009 at 11:05AM
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Good information rcbe and mownie.

I did a little experiment a little while ago. Before I fired up the machine to do another round of mowing, I remove the shroud on the top of the engine to be sure there was no debris around the coil. I found a little dust but no caked on debris. I did notice some crud on the ignition module so I cleaned that up. Then I remove the Kohler fuel filter which left just the in-line fuel shut-off valve between the gas tank and the carb. I finished cutting the lawn, which took about an hour, and the machine ran great. I usually dies about 1/2 hour into the job. I'm still not convinced that the fuel filter is the problem but it's looking very guilty. I read on another post that said Kohler recommends a 75 micron filter p/n 25-050-21 for my model engine.

I'll keep you posted.

Thanks to everyone for their advice.

    Bookmark   May 24, 2009 at 4:27PM
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I have a the same problem. Its a craftsman Kohler Pro 17hp. Ran great for ~5 yrs and then suddenly has this problem.

Problem: Anywhere from 10 minutes or 1hour into mowing it stalls out. At first I replaced the air filter. Then the fuel filter with one that you can see into. (not the kohler filter- more on that later) Tank is about 1/4 full.
-Mowed for 1/2 hr and it stalled out. Looked at the fuel filter and there was no gas in it. Removed the gas gap to check for venting problem- still no gas in filter. Then I pressurized the tank mouth. This worked, fuel rushed into the filter. Ran for 5 minutes and stalled out again. (long enough to burn the gas in the line)
-Suspecting a clog in the fuel line, I replaced the line from tank to filter. There was no debris in the tank, filter or line, but I replaced it anyway. Use same diameter and length of line, same routing. Tank now is 1/4 full of fresh full. Also checked, and the fuel shut off solenoid has good electrical connection. Mowed for 20 min then same problem.
-Thinking that more fuel pressure might help, I filled the tank to the brim and mowed for 1 1/2 hrs with no problem. (gravity pressure)

My thoughts:
-This is my parents mower, so i'm not real familiar with it. Maybe they always kept the tank full , but it seems that the mower should be able to run with ANY amount of fuel in the tank
-Fuel filter can NOT be the problem. Fuel flows into the cavity of the filter and THEN though the element. Even a clogged element would sill have fuel on the supply side.
-It has nothing to due with spark/ignition. The problem ALWAYS and only occurs when the filter runs dry.
-Could it be vapor lock? Why would the carb let vapor back into the fuel line? What about the fuel line getting too hot and boiling the fuel? I dont remember there ever being insulation being there.
-One more thought on the fuel filter, could the element not be letting vapor escape from the carb side and bubble back to the tank?
-I wonder if line routing could be a problem. It doesnt seem to have much slope on the line between the tank and carb.

Any thoughts/suggestions are appreciated. Thanks

    Bookmark   May 25, 2009 at 9:56AM
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I assume you read this entire posting. Like you, I swore that the problem wasn't the fuel filter. The machine ran great with the filter that came with it. I replaced it with a filter that Sears told me was the replacement to the didn't work. I installed the Sears recommended filter with Kohler filter 24 050 10 that the local power equipment dealer recommended...that was short lived. Yesterday I removed the fuel filter entirely and the machine ran non-stop for about an hour. That's the longest it's ran in a year. As I said in an earlier posting, "I'm still not convinced that the fuel filter is the problem but it's looking very guilty." I've spent th last couple of hours rsearching which is the correct filter and t loks like it's 25 050 21-S. Check out the Kohler site.

    Bookmark   May 25, 2009 at 10:33AM
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****Could it be vapor lock? Why would the carb let vapor back into the fuel line?****** Vapor lock does not occur because "the carb let vapor into the line. "Vapor lock" is a condition that occurs when temeratures (ambient + machine) rise high enough to "vaporize" the liquid fuel in the fuel lines and/or fuel pump. Vapor lock almost always happens (if it's going to) AFTER a hot engine has been shut off in hot weather. Because vapor in the lines and/or fuel pump actually "absorb and return" the pressure pulse created by the pump, WITHOUT allowing any fuel to be delivered or moved, vapor lock will cause the engine to act like it's out of fuel (it is) until the temperatures cool enough for the vapors to return to the liquid state. Vapor lock was once a real headache to motorists in the "old days". In hot weather, you could cut your engine off and two minutes later it refused to start again because in that short time.....vapor lock had occurred. Pouring cooling water on the fuel pump and fuel line to carb would cause the "vapor head" to collapse and allow for restarting the engine. Now days, electronic fuel injection and the required electric fuel pump have virtually made vapor lock "disappear like a vapor".

    Bookmark   May 25, 2009 at 9:20PM
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had the same issue recently with my craftsman 15.5 kohler. didn't read all the above post just skimed. on my mower the fuel filter sits on top of the oil filter with a small clip that holds the fuel line in place. after going through most of the stuff mentioned above, i took the fuel line out of the clip and let the fuel filter lay down on the side of the oil filter, it filled up immediately and hasen't missed a beat since. might be worth a try on yours.

    Bookmark   May 27, 2009 at 4:10PM
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So that's what that clip is for. I thought the throttle cable went in there but the cable was too stiff to fit in. The clip has always been empty. The fuel line on my tractor has always hung next to the oil filter but thanks for clearing up that mystery troy88.

    Bookmark   May 28, 2009 at 12:11AM
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I sure am hoping that you guys are still reading this forum now a year later cuz I have the identical problem in the same tractor/engine/HP...
I have changed fuel filters- though with generic type - have remove rubber donut from fuel solenoid plunger and installed in-line manual shutoff [learned THAT the hard way].
I can report that when stalling occurs, I shut off fuel valve and confirm having plenty of fuel in the carb bowl [though filter "appears" empty. I have also confirmed that I do have SPARK. The engine will not restart until about 5-8 minutes and not until I can visually detect fuel filling the filter from the tank side. And yes I have loosened the cap thinking vent problem.
Is the problem a heat-sensitive ignition module???
Has anyone definitively solved the problem or are all us Craftsman 17HP Kohler owners cutting our lawns in 10 minute spurts???? Spare me!

    Bookmark   May 5, 2010 at 4:34PM
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hi i have a 2003 craftsman lt 2000 with a 17hp and it keeps stalling i bought it new in 2003 it always had an engine stunble but would not do it all the time so i could not bring it back and have them check it out but 2 weeks ago it stalled all the time every 10 to 15 min i thought it was a safety switch so i checked one at a time but not the problem i rebilt carb i found fuel filter empty changed fuel filter but it kept stalling then i took filter off and put a tube in place of filter and it runs perfect so now i have to get a kohler filter try it it worked for me

    Bookmark   May 26, 2010 at 10:05PM
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My GT500 w/25hp Kohler does this same thing. I have checked the coil after it quits, and both plugs spark, I have been advised to clean the fuel cap vent (which didn't make a difference), I have replaced the fuel filter, and fuel pump as well as the breather tube. Nothing has changed the fact that it quits after about 30-45 minutes. I have taken it to 3 different repair shops and none of them can find anything wrong with it. 2 of them suggested either mowing without the fuel cap, or drilling a bigger hole in it. I am wit's end.

    Bookmark   June 9, 2010 at 4:50PM
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Kohler engines are finicky about wanting a KOHLER fuel filter (even the very specific p/n) designed by Kohler for that particular engine. Try using aftermarket filter brands at your own risk.

    Bookmark   June 9, 2010 at 7:13PM
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WOW! and I thought I was the only one experiencing this problem. I've seen it on this site several times. Mine does the exact same thing, runs fine for 30 mins give or take, then acts like it can run against a load, stalls. fuel filter looks dry.
Im going to get a filter in the morning p/n 25-050-21-S and see how that works.

    Bookmark   August 12, 2010 at 2:45AM
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Sorry for the long post, but I have a bit more to add to what folks have mentioned thus far that might give some insight into the problem. I have been battling this issue for two years and it is getting worse as time goes on. After it started, I replaced the filter with one of the original white filters. The problem continued, but the mower would run for about 45 minutes before stopping again. In time, I replaced the filter again. This time there were no more of the original style, just the clear cone shaped ones. This might be one of the issues. With the filter being clear, I too can see that gas is not getting through the filter. When the problem first started, there was pressure built up on the fuel tap cap, so I'd run with the cap being loose. This worked at first, but not now. Now, it will still stop running even with the cap off. I beleive that the issue is between the filter and the carb because most times when this happens, I disconnect the fuel line from the carb side of the filter and can blow the remainder of the fuel through the carb, reconnect it, see the filter fill with fuel and the engine starts right and runs for another few minutes. However, sometimes I can not blow the air and fuel through the line. When this happens, I let it sit for awhile, then try it again and it works and runs for awhile longer. Can somonee explain in detail how the solenoid works, how it can be tested, can it be bypassed????

    Bookmark   August 21, 2010 at 2:08PM
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I don't believe the fuel solenoid is causing your problem.
I would be more suspect of a weak fuel pump.

To test fuel pump output, remove the fuel hose from the inlet nipple of the carburetor. Hold the end of hose in a clear beverage bottle while a helper turns the key to crank the engine. If the fuel pump is in good health it will deliver strong and consistent spurts of fuel into the bottle. Expect a spurt of fuel to coincide with each stroke of a piston.

The fuel solenoid moves by spring pressure to block the main jet fuel passage when the key switch is turned OFF.
Turning the key to RUN or START causes the solenoid to pull the plunger off its seat in the main jet to allow fuel to flow through the main jet. The purpose of the fuel solenoid is to prevent or minimize afterfire out the exhaust/muffler when the engine is shut off when hot.
And to answer the query about testing the fuel solenoid, read below.

Have someone switch the key from OFF to RUN while you hold your finger on the fuel solenoid. You should be able to feel and hear the faint click of the fuel solenoid when the key is turned ON and OFF.
If you are unable to feel or hear the fuel solenoid operating, check to make sure that 12 volts are present on the hot wire at the fuel solenoid connector when the key is in the RUN position. If 12 volts is present, check the ground wire for the fuel solenoid (if it has a separate ground, some do not). If it has a separate ground wire, it usually grounds directly to the carb. This ground wire end terminal sometimes breaks off or gets corroded. If corrosion is found, the screw that holds it in place will be hard or impossible to remove from the carb. In case of corrosion, I have found it best to snip the wire free from the terminal and splice an extension wire with a new eye terminal and relocate it to the nearest suitable screw elsewhere on the engine, just make certain not to attach it to a plastic part.
If the wiring appears intact and sound, but you can't feel or hear the fuel solenoid working, remove the solenoid from the carb and check to see if the plunger is stuck. Check it by pushing it in with a finger tip. The plunger should push in pretty easy and pop right back out when finger is removed. If the plunger is sticky at all in either direction, flush the plunger and the plunger hole out with spray carb cleaner. The plunger can be "bench tested" by connecting the wire connector ends across a 12 volt source, observing the correct polarity.
If the plunger does not draw into the solenoid body when the wires are connected to 12 volts after a thorough cleaning of the plunger, replace the fuel solenoid.

    Bookmark   August 21, 2010 at 2:52PM
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Mownie, thanks for the quick reply and info. That is what I was thinking that the solenoid did. My tractor doesn't have a fuel pump, as the fuel tank is located under the hood in the engine compartment as apposed to under teh seat. I have cleaned out the plunger and hole several times with carb cleaner since the issue started, but never noticed any improvements. If the plunger were to stick from time to time, this might be the reason why from time to time I can not blow through the fuel line towards the carb, right?? Should I be able to blow through the fuel line with the key turned to the off position? I have been putting off cutting the grass today because of the issues, but am heading out now and will check to see if I can feel the plunger move.

    Bookmark   August 21, 2010 at 5:13PM
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OK, you don't have a fuel pump, scratch that off the list.
It is very near impossible for the plunger to operate freely freely and then just stick. Problems with fuel solenoid plungers typically result from fuel varnish after a very long storage period, like a year or 2 stoage time with no in between uses.

I presume you are "blowing" the manual method using your lips. Nothing wrong with that as long as you are careful about getting your face out of the way quickly when you let go of the hose, if the hose is blocked, gas could possibly surge backward out of the hose and get you.

The fact/detail that you can't seem to blow through the hose to the carb would not indicate anything about the plunger, because if the key is off, the plunger should be seated and blocking the main jet anyhow.

The very first "obstruction device" in a carburetor is the float needle valve. The needle valve closes off the fuel flow into the carb from the fuel hose when the float bowl fills to the specified level. In fact, it is the float rising in the fuel that exerts the pressure on the needle valve to cut the fuel off when the bowl is full.
When the fuel in the bowl is consumed, the float drops and once again allows fuel to enter the bowl so the engine has a steady supply of fuel in the bowl.
The times that you are unable to "blow through" the fuel line are when the float bowl is full of gas and the eedle valve is closed, effectively preventing additional fuel from entering the carb, even if there is you on the end of the hose blowing like the big bad wolf. The needle can resist the power of a fuel pump (where applicable) and it can easily run you out of breath with no problem.

I suggest you might want to clean out the fuel tank to see if you have something "growing" in there. Varnish can form flakes, certain types of algae seem to fare well in the ethanol sea of today's gas formulae, so you might have some material in the tank that is randomly sealing off the fuel hose nipple in the tank.
As for fuel filters, I don't use any OEM filters in any of my tractors or mowers!!
I buy an automotive fuel filter from the auto parts store that will fit the fuel hose, which usually means 1/4" hose.
These filters have more than enough capacity to filter the fuel without creating any restriction to low volume.

    Bookmark   August 21, 2010 at 6:02PM
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I tested the solenoid as you mentioned above, I can both feel and hear it move. I filled the fuel tank to the top before starting to create more pressure, but that did not seem to help as it cut out about 5 - 10 minutes into the ride. It still cut out 5 or so times in the course of a little over an hour. Instead of removing the hose as I mentioned above, I tried what someone else mentioned above, create a seal and blow into the fuel tank. In doing this, I could see the fuel enter the dry filter as well as hear the fuel being pushed into the carb area. Each time it started right up. several times since the issue started, I have removed the tank, emptied it, put some new gas in it and splashed it around, then dumped it out. It never really seemed to help with the issue. In the past I have blown up through the bottom of the tank, but never noticed any clog. The most recent was two weeks ago. I will do it again, but this time will spray the carb cleaner up through the bottom of the tank. Is the small hole in the bottom of the tank a specific size? Would it create an issue if I were to make it larger, or is it controlling the volume of the fuel flow?
Another thing that I wanted to mention was that the filter that I have on there is bigger than the original one and therefore will not sit in the same postion as the last original one, unless I put on a fuel line, which I will be doing when I flush the tank again. With this tractor not having a fuel pump, the position of the hose should affect the flow, correct? If the hose is not always flowing toward the carb, this could creat an issue, right? If so, the design is bad in that the bottom of the fuel tank, the hole in the frame for the fuel line and the carb are not positioned well for gravity feed. I know that the mower ran fine for a year or two at first and that this may not be the problem, but wanted to mention it. I have thought of raising the tank another inch (as hight as I can) and drilling a new hole in the frame for the fuel line, but want to get folks opinions on this before I do.
Speaking of the tank, all of this started around the time that I noticed a dead spider in the fuel tank. I removed him and cleaned the tank. But the probelms never went away.
I will pickup a new auto fuel filter.

    Bookmark   August 22, 2010 at 11:36AM
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Do not try to enlarge the opening in the fuel tank nipple, that will not help the situation and could very well lead to breaking of the nipple itself.
There are two things (not counting the filter) that "restrict" the fuel flow.
The first "restriction" is the carburetor needle valve. This is not a "fixed size" restriction but instead is variable from completely clsed when the float bowl is full to completely wide open if the float bowl empties for some reason.
The other restriction to fuel movement is the jet (or jets) that meter the fuel fed to the induction system. Jets are considered "fixed restrictions" as they do not change size automatically.

Your problem might be the needle valve in the carb is sticking in the closed position and when the bowl runs out of gas, the needle is either not letting any gas into the bowl, or it is letting too little for the engine to stay running on.
This could be consistent with what you are hearing when you blow on the tank. You might be exerting enough fuel pressure to push the stuck needle off its seat and let the fuel flow again. Whether it is the needle valve itself, or the float that is hanging in the up position I couldn't tell you.
If you have the OEM fuel hoses still in place, replace them with new hoses. The old hoses might be dissolving and causing a sticky film to coat the needle valve and that might be sticking the valve to its seat when closed.

Regarding the orientation or positioning of a fuel filter, I like for the filter to lie horizontally with the inlet on one side and the outlet on the opposite side. I don't ever place a filter with the inlets and outlets pointing up and down. My reasoning (or opinion if you like) is that if the filter is lying horizontally, when the fuel enters the larger diameter of the filter case, the flow becomes very quiet and slow, allowing a chance for fuel borne trash and water to settle to the lower portion of the case, while the lighter fuel just sweeps right over the top of that stuff without remixing it or stirring it up.
If the filter points up and down, the fuel borne junk either settles to the outlet end of filter if that end is down, or the junk just continually rises and falls into and out of the inlet end of the filter if the inlet end is down. I like my filters nice and level :^)

And don't bother troubling yourself to increase the altitude of the tank, you will gain no noticeable increase in fuel flow. Replacing the old hoses could make more improvement in flow than the height of the tank.

    Bookmark   August 22, 2010 at 11:05PM
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Sorry for the delay in posting an update. I repeatedly cleaned the inside and outside of the carb, fuel tank, float valve and fuel cap with carb cleaner, replaced all of the fuel line and fuel filter as well as installed a fuel shutoff, I installed the new filter directly under the fuel tank, instead of in its original location on the side of the engine. The total cost at the auto parts store was under $20. I have cut my grass twice since doing this work and the tractor has never stalled nor hesitated. The tractor has not run this good this for the past couple of years. Thanks for everyones their postings and input. Hopefully more folks will be able to correct thier tractors issues with the info. One last thing, I strongly encourage everyone to install an inline fuel shutoff. The last time that I tried to use the tractor before making all of the changes, fuel started flowing from under the carb cover right next to the hot engine. The only way to get the fuel stopped was to disconnect the fuel line, Now that I have the $5 shutoff installed, I manually close the valve.

    Bookmark   November 6, 2010 at 1:42AM
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I didn'read all the entries above but hasn't anyone replaced the ignition module? I have replaced mine 2 times and each time it works for a while then fails again which may indicate that it is not the problem or the Ignition modules are crappy. You would think Kohler would have a solution by now

    Bookmark   April 2, 2011 at 3:50PM
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Foster, welcome aboard!
But, if you suppose that every thread posted here is always carried to resolution...........and the results are then promptly posted............I hate to disappoint you.

While we do have a high rate of satisfaction, and sometimes get feedback and/or discussion..........we also have a lot of drop in "one hit wonders" as well (as do all public forums).

So, maybe the final verdict has not been posted yet, perhaps it never will be.

And, don't think of every old thread as a "cold case" waiting to be reopened. If the original poster does not update a thread inside of about 2 is probably dead in the water.

    Bookmark   April 2, 2011 at 5:07PM
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Had problem with intermittent stalling at first (anywhere from .5 to 1 hour into mowing). Then tractor would start and stall immediately or not start at all. Turned out to be the fuel shutoff solenoid. Bench testing showed that it would retract sporadically. Removed tip but it still seemed to hinder fuel. Snipped plunger head completely off. Mower works great now. Installed manual shut off valve.

    Bookmark   July 24, 2011 at 3:04AM
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I am convinced I have the same issue with the fuel shutoff solenoid. I am not sure how to remove the tip or snip the plunger head off. Can you give me more detailed instructions?


    Bookmark   August 6, 2011 at 3:12PM
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A more strategic way to test whether the solenoid valve is really at fault or not is to forcefully press the plunger into the solenoid body holding it tightly with a finger tip.
Then with the solenoid valve plunger completely bottomed out, jam a wooden toothpick into the space between the plunger and the inside of the threaded barrel. Once the tooth pick is holding the plunger depressed.........break the tooth pick off nearly flush with the barrel.
Then, reinstall the solenoid to the carburetor.
The solenoid valve is now effectively defeated and will allow fuel to flow into the carb main jet in the same manner as if the plunger was removed.
If the performance/behavior of the engine remains the same as before..........then the solenoid valve IS NOT at fault.
Using the tooth pick trick allows for returning the solenoid to operational condition if it proves not to be the culprit.
Otherwise you are going to have to pay around "$100 plus" for a new solenoid because you destroyed the original based on "guess work".

    Bookmark   August 6, 2011 at 3:30PM
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I finally got a chance to try your suggestion. Can you verify that the plunger is what I have circled in the picture in the attached link?


Here is a link that might be useful: plunger

    Bookmark   August 20, 2011 at 4:45PM
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Yes, the plunger tip is encircled.
If you can get a very short bolt that has identical threads as the threaded portion of the barrel, you can transfer the sealing washer from the solenoid threads to the bolt and use the bolt as a plug so you can try running "minus solenoid" as a test.
Take the solenoid with you an shop for a bolt that is no longer than the threaded part of the solenoid.
To match threads, try some nuts until you find the match, then buy the bolt with the same threads.
As a final check for thread match, lay the bolt threads on the solenoid threads and see if they "mesh" perfectly.
If the threads do not fit snugly to each item, wrong threads.
This specific configuration of the tip (rubber valve tip) does not facilitate the toothpick idea very well.
You can try to pull the plunger out of the solenoid body.
If the plunger can simply pull out (without much resistance) just leave out the plunger and thread the solenoid back into the carb bowl for your test.

    Bookmark   August 20, 2011 at 9:05PM
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Weak valve springs will almost always reveal themselves as a high RPM "flutter" or fade.............but, usually before that will happen, a pushrod will get tossed out of socket and the affected cylinder will become completely dead until repairs are done.

As far as a weak valve spring causing some local pressurization that might cause fuel to flow backward in the carb. No.
The clearance of the needle valve to its valve seat in the carb is so slight that any tendency for reverse flow in the carb would push the needle valve against its seat, thus acting like a check valve.

    Bookmark   August 21, 2011 at 11:42AM
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Thanks mownie. I took the black plastic/rubber tip off the plunger and this seemed to work. The mower did not ever die, started when warm, and the engine did not hesitate like it wasn't getting gas when going up or down hills. I did keep that tip in case I need to put it back on.


    Bookmark   August 21, 2011 at 6:31PM
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I wonder if these rubber tips might be affected by ethanol causing them to swell?
Another possibility is than because the solenoid mounts vertically on this carb, the bore in the solenoid for the plunger might be collecting some sediment below the end of the plunger which is preventing the plunger from pulling fully open when activated.

    Bookmark   August 21, 2011 at 9:00PM
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I recently began having the same problem with a 26HP Kohler. I replaced plugs, and fuel filter and it happened again after about 3 hours use. I removed the hose from tank to fuel filter and there was a small stream of gas. I blew through the hose until I heard bubbles in the gas tank and a large stream of gas came out. It ran fine for about an hour. Blew through the hose again and it would run fine. I replaced the fuel hose and so far it has worked. I suppose there was a pin hole in the hose causing a loss of fuel pressure or tank pressure. You might blow through the hose and see if you have the same symptoms.

    Bookmark   November 9, 2011 at 8:05PM
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I have one of those Kohler/Craftsman tractors here as we speak. 17 h.p., and doing the ten second run/quit trick. I got it as a gift. Looks well cared for, but owner got tired of problems with it. Didn't ask me to fix it, just hauled it in and said to keep it.
In our area, we have a Citgo Station where i buy my mower and truck gasoline, and haven't had any problems like i have read about, as posted by folks in other geographic areas.
I'm going to try those tricks with the float bowl solenoid valve, as the quick stall is most of the problem.
My other problem is where to store them over winter. I've 'bout run out of storage. Guess the tarp trick will have to do, and bring in the good batteries.

    Bookmark   November 25, 2011 at 8:53PM
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An addition to my problems: Or, a solution to them:
Today, i removed the new fuel filter and replaced it with a short length of copper tubing. Started the engine, and it ran until i shut it off. About 45 minutes. I mowed dry leaves, long and short grass, damp leaves, and anything else. Never missed a beat-worked quite well.
Now--all i need is a place to stuff it until Spring. Or, find a buyer for it.
With any type of filter installed in the fuel line--it would not run very long, if at all.

    Bookmark   November 28, 2011 at 7:05PM
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rusty - some of the kohler engines are "picky" about the right fuel filter - best to stick with what kohler recommends - or you may well be doing a carb overhaul very soon to get dirt/trash out...

    Bookmark   November 28, 2011 at 7:19PM
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Yes, i have read about that problem.
But-- i Got it stuck in the garage door opening yesterday, and had to wait until today to get it unstuck, as my helper was busy else-where. The garage door opens onto a dirt floor, with a resident ground hog that winters in it amongst the machinery.
So, it started ok, and with some help, i got it back outside. Then, when i tried to drive the pickup up the sloping dirt driveway---it wouldn't get any traction on the wet leaves and dirt. Finally burned my way up, then drove tractor up behind the house, covered it and went in for supper. Tomorrow---another day. But-tractor runs great, now that i removed the gas filter, and installed the copper pipe/tubing. RJ

    Bookmark   December 1, 2011 at 7:34PM
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I had a Cub Cadet with same engine - same problem.

Root cause was a blown muffler that directed exhaust down the frame rail. The fuel hose was routed in the frame rail. After 30 minutes heat would cause gas to boil in the fuel line and shut me down. I was 3 weeks figuring that one out. I fixed the muffler and foamed the opening in the frame rail. NO MORE PROBLEMS.

    Bookmark   December 5, 2011 at 1:16PM
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Well, it's been a few years since my initial post, but clearly this is common problem and I wanted to share what worked for me. I had tried every brand of fuel filter I could find, running without the fuel tank cap, replacing the fuel line, and cleaning out the carb. It turns out that the seat safety switch was bad. Evidently it worked most of the time, since I could mow for awhile before it would stall. I was getting near the end of my list of things that might be bad. I removed the switch and put in a jumper wire, and it's never stalled out since - that was the beginning of last season. I do plan to get a new switch.

    Bookmark   July 11, 2012 at 9:49AM
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Thanks for the update moe.
Hopefully the new switch will work well into the future.

    Bookmark   July 11, 2012 at 11:50AM
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I like so many others have this engine and same problem and have so for many years. Recently a new issue has evolved that might have a bearing on all. As one person mentioned, there had been a puff, then a large cloud of blue smoke when starting for the first time after a week of being idle. That graduated up to a gas puddle right under the muffler. I then noticed that 1) upon sitting for a week, raw gas would spit out of the exhaust, 2) a tank that was half full at the end of a mowing session would be empty (verified on several occasions) and 3) the dip stick would show the crank case to be FULL to the top of the dipstick. Also, the oil was water thin and smelled like pure gasoline. The temporary fix to this is the addition of an in-line shut off valve.

Now here are two related but opposite issues. One of too much gas flow (not shutting off when idle) and one of too little (stalling from time to time). My stalls have always been averted by a quick application of the choke as soon as the engine sputtered followed by loosening the gas cap.

Now, what is common in all of this? The float and needle valve? Has anyone replaced these items? Even if my fuel shutoff solenoid is not working, a full bowl / good float / needle valve should keep gas from leaking past and filling the crank case. A messed up float and needle valve could also cause stalling and poor fuel flow.

I'm thinking of the shotgun (and expensive) approach, replace fuel lines, factory filter, replace carburetor assembly and for good measure, jumper out the seat safety switch (temporarily).

    Bookmark   April 17, 2013 at 2:11PM
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***" The temporary fix to this is the addition of an in-line shut off valve."***
No, that is the permanent fix.
The "temporary fix to this is to replace the float and needle and trust them to remain reliable".
The fuel solenoid valve has nothing to do with keeping fuel from leaking out of carb when in storage. The fuel solenoid valve is only there to minimize "after fire bang" when the engine is shut down hot.
Some people think that the needle valve's job is to keep fuel from entering the carb under any circumstances and that simply is not true.
The float and needle valve is there to maintain an adequate and somewhat constant level of fuel in the bowl for optimum fueling of the engine.
A float and needle can leak a slight amount of fuel when the engine is shut off for storage and that will drown an engine in the classical fashion of gas in crankcase and flowing out exhaust, etcetera. That paltry volume of fuel leakage past the needle might not be enough to cause even a rich mixture in operation of the engine but given enough time in storage it will empty a gravity feed fuel tank.

    Bookmark   April 18, 2013 at 12:21AM
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Fixed it.

Just wanted to follow up with what fixed my problem. you can find the description of the problem somewhere in the thread above- do a ctrl F on my name. (may 2009)

Fast forward 4 years
My mom moved to a smaller house and didnt need the mower and I got it. Convinced that it was a slope issue with the fuel line, I shorten it as much as possible so that it would not have a constant upward slope to the gas tank.
Still didnt work.

Then I raised the fuel tank about 1 inch. The extra height allowed for a better (steeper) slope from the carb to the tank.
Fixed it.
Been mowing several months with no issues at all.

hope that helps somebody out there

    Bookmark   July 2, 2013 at 6:01PM
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Rusty: I tried what you did - I replaced the fuel filter with a length of copper tubing. My mower worked beautifully! To me, that means my problem is with the fuel filter, PERIOD.

I bought a 25 050 22S1 at Tractor Supply (Kohler-made). Mower stalls. (Mine stalls when going up hill). I put the tubing back and of course it works fine.

I need to try the 25 050 21S (this is the part# for the filter on the Kohler website). That will be my last effort. If that doesn't work, it will be the tubing as long as the engine lasts!
By the way, my mower is a Poulan Pro 42

Thanks Garden Web and all the participants.


    Bookmark   June 24, 2014 at 9:45AM
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This seems to be a Craftsman LT2000 continuing problem. I picked up a used LT2000 runs fine but now is doing the same as others have mentioned, it will slowly act like it is running out of gas when I am 2/3 rds of the way through cutting the lawn. I am guessing I will start by reversing the directions of the new fuel filter and if that doesn't work will purchase an official Kohler replacement. Thanks for the information. if anyone has more on this please post.

    Bookmark   June 24, 2014 at 1:40PM
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schmb1 - if you have a kohler engine in that machine, get the correct kohler filter - now. And , it will have an arrow on it for fuel flow direction.

    Bookmark   June 24, 2014 at 2:40PM
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I had the same problem with my mower that has the 15.5hp kohler. so here's what i did.
cleaned fuel line and gas tank
replaced fuel filter
removed fuel filter
changed fuel pump
changed carburetor
changed fuel octane to premium
changed the uncle sam switch
cut the tip of the uncle sam switch off with wire cutters
NONE OF IT WORKED so here's what i did then
bought a electric fuel pump connected it to the fuel line and wired it to a switch now when the motor wants to cut off i just flip the switch turning on the electric fuel pump. I let it run for a few minuets to build up pressure and shut it off. Then when the engine try's to shut off again i turn on the fuel pump again and it works. Tomorrow i am going to find a fuel pressure regulator and bypass the mechanical fuel pump and try to make the engine run on the electric fuel pump. The fuel pump is a mr gaskets brand and puts out 2-3.5psi.
The pump, wires, switch and connectors cost me about $80 but i am now able to mow yards without the engine shutting off. I don't know the exact reason for the problem but here's my theory. The motors get a little age wear and tear on them and the mechanical fuel pump works by the camshaft of the engine and over time the lobe wears down on the cam shaft that powers the pump so the pump doesn't work properly and gravity alone is not enough to supply fuel to the engine. because if gravity was enough the engine wouldn't have a fuel pump. And that's all i have to say about that folks i hope it helps you out.

    Bookmark   July 20, 2014 at 2:58AM
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I installed a fuel pressure gauge in the fuel line to see exactly what the electric pump was producing and it actually puts out about 8psi. Which was too much for the carb when by passing the mechanical fuel pump. So i installed the fuel pressure regulator and after playing with the adjustment i found that 3psi was the sweet spot. I just mowed for 2 hours and no problems. No stalling sputtering cutting off and no flooding the carb. It runs great so i do believe the problem is solved.

    Bookmark   July 20, 2014 at 8:01PM
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Hi again. Just an update....
I bought a genuine Kohler 25-050-21 fuel filter and put it in.
I'm sorry to report that the mower stalled.
I will run it with the copper tubing substitute - I'll call it the "stent" ! I'm not putting any more time or money into this machine.

    Bookmark   July 23, 2014 at 11:05PM
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For everyone with stall issues that are possibly related to fuel supply on a Command w/ no pump-2505007s is the filter to install. The 2505021s filter is spec'd also as a no pump filter, is the same micron rating- but is larger and shaped different. It CAN make a difference.

    Bookmark   July 24, 2014 at 12:11AM
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I remember reading on one of the forums a few years ago that Craftsman specified the incorrect fuel filter in the Owners Manual for a lot of tractors.
Gravity fed engines were listed as using the filter for fuel pump engines.
That filter has a smaller micron rating and may not do the job under gravity fed conditions.
Check the Kohler Operators manual when in doubt for the correct filter.

    Bookmark   July 24, 2014 at 2:36AM
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Tomplum: I will make a note of that filter # and check with the small engine shop that I deal with. I've been wanting to ask them about this problem anyway.
Thanks much! BD

    Bookmark   July 28, 2014 at 12:33PM
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Tomplum: I will make a note of that filter # and check with the small engine shop that I deal with. I've been wanting to ask them about this problem anyway.
Thanks much! BD

    Bookmark   July 28, 2014 at 12:34PM
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Yeah, this filter thing can be a pain. Newer models for years they have installed the 21 filter on. But, they don't always work on every machine. Maybe the head is not quite high enough on the old ones. I like the guy above that raised his tank an inch. Wish you could do that on all of them!

    Bookmark   July 28, 2014 at 8:26PM
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