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Briggs 16 hp runs slow and no power

Posted by floridacruiser777 FLORIDA (My Page) on
Fri, Jul 20, 12 at 13:44

Was mowing when it acted like it was running out of gas. Checked the gas and it was OK.

Checked the air filter and gas cap for blocked vent. Everything OK.

If and when it starts, it runs like it is on idle even tho it is on high speed.

What is the long cylinder at the bottom of the fuel bowl with two wires? It seems like a friend of mine had the same problem and he replaced this part and fixed it.

All suggestings appreciated.

Model 31C707 Type 023081 Code 031010ZE


Follow-Up Postings:

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RE: Briggs 16 hp runs slow and no power

The thing on the bottom of the carb is the "after fire" solenoid. It needs 12V DC to it when the engine is running. It should click when the key is turned to on position. IF you suspect it, remove it depress the plunger, wedge a tooth pick beside the plunger and break the tooth pick off and see it that helps. Be aware that gasoline will run out as you remove the solenoid and will continue unless you shut the gas off from the tank. IF yo do not have a shut off valve, pinch the fuel line shut with a clamp, vise grips, etc.

Does the engine have a fuel pump? IF so, is the vacuum line running from the engine to the fuel pump OK?

Walt Conner


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RE: Briggs 16 hp runs slow and no power1

As an after thought, IF the above does not turn anything up, remove the valve cover and see if all is well in there, push rods in place and working, not bent, etc.

Walt Conner


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RE: Briggs 16 hp runs slow and no power

It doesn't click when I turn the key on. Would this part be causing the problem I'm having?

Thanks~~~~Ron


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RE: Briggs 16 hp runs slow and no power

Isn't that what Walt told you to do??? BBLLL BBBLLL!


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RE: Briggs 16 hp runs slow and no power

The thing on the bottom of the carb is the "after fire" solenoid. It needs 12V DC to it when the engine is running. It should click when the key is turned to on position. IF you suspect it, remove it depress the plunger, wedge a tooth pick beside the plunger and break the tooth pick off and see it that helps. Be aware that gasoline will run out as you remove the solenoid and will continue unless you shut the gas off from the tank. IF yo do not have a shut off valve, pinch the fuel line shut with a clamp, vise grips, etc.
Does the engine have a fuel pump? IF so, is the vacuum line running from the engine to the fuel pump OK?

Walt Conner

Walt: I don't want to break anything. The solenoid is a small cylinder and I don't see anyplace to put a wrench on it to take it off. How do I get it off? Thanks


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RE: Briggs 16 hp runs slow and no power

Got it off. The plunger was stuck down in the key on position. When I pulled the solenoid out, the bowl was full of gas.

I cleaned up the plunger and it works perfectly. Put it back on and still won't start. Pulled the solenoid out again and the bowl was full of gas. Tells me the float is working.

What's next? Checked the spark by pulling wire and it is fine.

Somebody mentioned ignition module failing. Where is it and how do I test it?

Thanks~~~~~Ron


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RE: Briggs 16 hp runs slow and no power

If the ignition module fails, you have a weak to no spark.

Whens the last time you installed a correct for the engine fuel filter & spark plug.

Either of those can cause an extreme loss of power if allowed to get bad enough.


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RE: Briggs 16 hp runs slow and no power

Check my Update thread for more information posted today (21st). 16Hp Briggs still not running.


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RE: Briggs 16 hp runs slow and no power

Nothing wrong with the Anti-Afterfire Solenoid. It switches back and forth fine. You unplug it and the engine stops running.
I put in a new spark plug, fuel filter and shut off valve in the gas line. Also...checked the cap for vent blockage.

Checked the spark while cranking and it is hot and jumps far.

Pulled the carbuerator and cleaned it. Didn't need it...it was clean as a new one. Blew through all holes and put back on engine.

NOW...The only thing I observed is while it is running at a slow speed (the only speed it runs) is that the black rubber hose running from the plastic elbow (where the air filter sits) to the top of the engine. It has no suction in or blowing out. WHAT SHOULD IT BE DOING?

I can get it to run if I prime it or put it on full choke and crank it alot. BUT...it is running at a fast idle even when the throttle lever is set on max for mowing.

It will not advance to max engine speed for mowing. Checked the throttle linkage and everything is working as it should.

Any and all suggestions would be appreciated. Thanks~~~~Ron


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RE: Briggs 16 hp runs slow and no power

"Any and all suggestions would be appreciated. Thanks~~~~Ron "

I made a couple @ 2:14 am.

Why should we make any more if you don't respond to the ones we make?


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RE: Briggs 16 hp runs slow and no power

If you would carefully read my post at 14:03, I addressed all your suggestions and still have the same problem. Thanks for reading~~Ron


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RE: Briggs 16 hp runs slow and no power

This Briggs engine is almost 9 years old. When was the LAST time that you checked and/or adjusted the valve lash on the engine?


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RE: Briggs 16 hp runs slow and no power

Never been checked. Is it something I can do or does it have to go to the shop?


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RE: Briggs 16 hp runs slow and no power

I don't see how one can edit their post so I'll ask another question.

If it is something I can do....would someone be so kind as to walk me through it step by step. I have experience with doing valve lash on V-8 car engines. I also have feeler gauges and tools. Thanks~~Ron


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RE: Briggs 16 hp runs slow and no power

When you have the valve cover off, also evaluate if the amount the valves operate are about equal- or does one have much less lift than the other. You will also want to know that the the rocker studs are secure in the head and that the small stem caps are in place under the rocker. When you had the carb off, did the throttle shaft seem worn where it goes through the top of the carb? Valve adjusting instructions for these are all over the web. Intake clearance is set between .003 (best)- .005 and the exhaust is .004 -.006. Valve lash is set whilst the engine is cold and the piston is 1/4 past TDC after the intake valve closes.


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RE: Briggs 16 hp runs slow and no power

Just an idea here...is your governor spring broken or stretched? Could your throttle cable have slipped out of position? Air filter clogged? Its always these really simple things that can throw ya...I know...lol


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RE: Briggs 16 hp runs slow and no power

Thanks so much for you info on adjusting the valves. I can handle that as I've had experience years ago on old cars with carbs.

I'll get to it the first of the week and post how things turned out.

Ron


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RE: Briggs 16 hp runs slow and no power

Cleaned the filter, checked the spring and throttle cable and all looked good when I had the carb off. Thanks for your input!!! Ron


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RE: Briggs 16 hp runs slow and no power

Bad idea starting another thread as Bill said.

Time to check the amount of actual movement of the valves. Do they move about the same amount? Is that 3/8" or so? Pay particular attention to the exhaust.

Walt Conner


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RE: Briggs 16 hp runs slow and no power

I have enough info to do a good check the first of next week. Thanks to all for input and I'll keep you posted.


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RE: Briggs 16 hp runs slow and no power

Sorry, I missed the part about the new fuel filter & spark plug.

Just to verify the air cleaner is good, try a quick test with it removed.


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RE: Briggs 16 hp runs slow and no power

Air filter is fine and I ran it at slow speed (only speed it will run) after priming and cranking without it on. Same problem....Will not go to max speed even with the throttle set at max speed for mowing. Carb linkage is fine and throttle shaft looked and felt fine when I had the carb apart.

Again....thanks to all for your input. I'll post after I set the valves.


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RE: Briggs 16 hp runs slow and no power

I found a video on you tube for adjusting the valves. I'm ready now to give it a whirl. Thanks to all for your help.


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RE: Briggs 16 hp runs slow and no power

Do check the actual distance the valves move (as suggested) before getting too involved in adjusting them.

I have a hunch you have a "flat" cam (not uncommon in the 31 series engines).
I would expect the engine to run much better than described, if it was simply a valve adjustment issue.


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RE: Briggs 16 hp runs slow and no power

Thanks Bill for the headsup!!! I will look real close tomorrow before I do any adjusting.


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RE: Briggs 16 hp runs slow and no power

WOW...I think I got lucky!!!! I pulled the valve cover and immediately seen that the rocker arm on the Intake Valve (alum push rod) was pointing down intead of horizontal.

Under further inspection it seems that the rocker arm stud loosened up and backed out just enough to allow the rocker arm to drop off the push rod.

I rolled the push rod on a perfectly flat surface and it is not bent at all.

HERE ARE MY QUESTIONS: How tight should the rocker arm stud be and should I use thread lock? I would think I would need thread lock after what has happened. It looks like there is a small amount of thread lock on the thread from the factory.

ALSO...In tomplum's post on Saturday July 21stst at 18:50 he states to make sure the small stem caps are in place under the rocker. I have no idea what he is referring to about this item.

I carefully removed the valve cover and no loose parts fell out. What is he referring to (small stem cap)?

All input greatly appreciated as I want to lash the valves and put this back together tomorrow.

Thanks again for everyone's help~~~~Ron


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RE: Briggs 16 hp runs slow and no power

One more question........When I put the push rod back in to touch the cam, does it just sit in there or should I be able to feel some type of resistance?

Thanks~~~~Ron


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RE: Briggs 16 hp runs slow and no power

That high didn't last long. I got to thinking and went out and put the push rod in and rotated the engine around and watched the exhaust valve open and close. The intake push rod I had in my hand while pushing against the cam with pressure didn't move at all.

It looks like Bill was right!!!! It's hard for me to believe that the lobe on the cam is wiped clean with no movement at all as I pushed hard and rotated the engine.

Looks like I will it the Buy It Now Button on eBay and buy a brand new 16.5 hp for $449.00 including shipping.

Let me know what you think!!!! Ron


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RE: Briggs 16 hp runs slow and no power

"It looks like Bill was right!!!!"

I'd have sworn I was the one who suggested that, must be getting old.

Walt Conner


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RE: Briggs 16 hp runs slow and no power

Walt- Where d.o you think I learned that!
I was just filling in for you by proxy


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RE: Briggs 16 hp runs slow and no power

You want to be sure that the push rod is seated in the tappet, rather than resting on the block. I would be surprised if there were a completely flat cam coupled w/ rocker stud issues. If it comes to it, the cam is not very difficult to replace. For the rocker stud, clean the threads up and let it dry before applying red loctite. Valve caps are small round discs that slip over the valve stem.


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RE: Briggs 16 hp runs slow and no power

tomplum: How can I know for sure the push rod is seated in the tappet and not just resting on the block? When I slid the pushrod in, it just stopped and I assumed it was in the tappet.

When I first took the valve cover off, the rocker arm was hanging down (vertical) and the rocker stud just screwed out by my fingers. That's why I thought the stud just loosened up.

I wish I knew for sure before ordering a new engine.

You say the valve caps are small round discs that slip over the valve stem. So....I won't have to be concerned about that as I have not have the valve spring apart from the valve. Right?

Please advise and Thank You for your time. Ron


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RE: Briggs 16 hp runs slow and no power

"The intake push rod I had in my hand while pushing against the cam with pressure didn't move at all"

"You want to be sure that the push rod is seated in the tappet, rather than resting on the block. I would be surprised if there were a completely flat cam coupled w/ rocker stud issues"

Good point.

"You say the valve caps are small round discs that slip over the valve stem. So....I won't have to be concerned about that as I have not have the valve spring apart from the valve. Right?"

They are small round cups and they usually stay put on top of the valve stem but should check that they stayed in place as without the push rod in place, there is nothing holding pressure/clearance on them.

Walt Conner


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RE: Briggs 16 hp runs slow and no power

OK...I appreciate everyone walking me through this diagnosis. I used a flash light and looked in and saw the tappett and put the push rod in the tappet. Held firm pressure and turned the engine over numerous times and watched the exhaust valve open and close.

The intake push rod never moved. I called a local shop that always is the fairest and best price (mom & pop shop) been in business over 25 years and the owner gave me a price of $300.00 to replaced the cam. Plus extra if the valves and seats needed some work.

I'm not even going to attempt doing it myself. Maybe 20 years ago I would have accepted the challenge. Getting old with arthritis and old timers disease sucks!!!!

I can buy a brand new (2-year warranty) 16.5hp briggs for $449.00 with free shipping out of Atlanta, Ga from a distributor. I'm leaning that way and will make the purchase tonight if nothing changes.

Just pop the old one out and bolt in the new one and I'm back in business.

Ron


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RE: Briggs 16 hp runs slow and no power

Go for the new engine. Best deal between all the options. Good luck with the transplant.


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RE: Briggs 16 hp runs slow and no power

New engine ordered and should be here in a few days. My mower is in excellent condition and with the new engine ought to get many more years of service.

Have a good one!!!! Don't forget to stop and smell the roses once in a while.


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RE: Briggs 16 hp runs slow and no power

Does the new engine have the same charging system as the old?
Your engine as the dual circuit alternator.

You "might" have to swap the stator & flywheel to insure the electrical matches up with the tractor, without having to perform electrical "surgery".
That's a relatively simple task.


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RE: Briggs 16 hp runs slow and no power

Bill: I don't really know about the charging system. I reread the listing on my new motor purchased and it doesn't say anything about the charging system.

How will I know? Thanks for your input~~~~~Ron


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RE: Briggs 16 hp runs slow and no power

The connector plug coming from the alternator.


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RE: Briggs 16 hp runs slow and no power

Got the new engine this morning. Pulled the old one and installed the new one. Piece of cake!!!! It was a plug and play. Everything was as the old one including all the electrical connections. Operates perfectly!!!!

Many thanks to everyone for their input on my problem and install instructions.

Have a great summer and Happy Mowing!!!!

Ron


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RE: Briggs 16 hp runs slow and no power

It's great when they just "bolt up" isn't it!

What was this engine on? Just curious.


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RE: Briggs 16 hp runs slow and no power

This engine was on a 42" Craftsman riding Mower. Now I have a perfectly good old engine laying in the shop with the camshaft no good.

It would make somebody a good project for a few bucks ($85.00) for a new cam if a person knows how to take these things apart and repair them.

The engine really had low hours on it as it wasn't used in the mowing season for the first 7 years as we traveled in a motorhome for the summer months. I only used it about once or twice a month (2hrs) in the winter months here in Florida cutting weeds that had grown in the yard.

I was surprised when a perfectly running engine lost it's camshaft.

Oh well...........We are up and running again.


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RE: Briggs 16 hp runs slow and no power

I was curious what it was on because I've constructed a home made data base of Craftsman tractors.
That # didn't come up, but there's quite a few models with a -
31C707-0230-E1

Could you look up the Sears 917.xxxxxx number for me when you get time? Should be under the seat.


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RE: Briggs 16 hp runs slow and no power

917.273351 Here you go Bill.


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RE: Briggs 16 hp runs slow and no power

Thanks-
The OM shows the engine # I posted?????


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RE: Briggs 16 hp runs slow and no power

In my original post I gave the Model, Type and Code stamped on the Valve Cover.

Model: 31C707
Type: 0230E1
Code: 0310102E

If you put the model and type together you come up with your number. I guess we solved the great mystery.


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