Primer Bulb Replacement On Tecumseh Carb

itzbinniceFebruary 21, 2009

Greetings All,

My senior citizen brother-in law was given a 2007 Lawnboy Model # 10685 Insight lawn mower with a 6.5 HP Tecunseh engine.

Model # LV195EA with sens-a-speed.

Year 2007

Serial 270031236

The mower looks like it was used one time, it's immaculate.

It would not start but had spark. I was suspicious it was a fuel problem since when depressing the primer bulb it didn't appear any gas was being pumped into the intake manifold.

I took the carb off and removed the bowl, everything looked brand new like gas never went through it. I then took my air hose and blew through the red plastic tube coming from the carb side that extends into the air filter assembly.

When I blew the air through the primer bulb began expanding so it appears there is no leak there. I'm not certain if I did damage to the primer circuit by doing this test.

I was able to get the engine started by pouring a small amount of gas into the throttle body. By doing so it started right up and ran well so there is nothing else wrong with the mower other than the primer not functioning.

I took the carb and gas tank to one of the local repair shops and hoped I could pick their brains but the guy was not too bright and I ended up buying a bowl o-ring and bowl nut washer, also bought a new manifold gasket. He told me there was a leak somewhere and that it wasn't holding air pressure.

He said the new gaskets should do the fix. Not so, it behaves exactly like it did before, just does not seem to be pushing any gas down the carb.

Just wondering if there is some sort of diaphragm under the rubber bulb that could be the problem. I tried to remove the bulb assembly to inspect but looks impossible to remove the round metal retaining clip that holds it. I thing by prying in there I will put a hole in the rubber bulb.

Is there a method of removing without damaging the bulb?

I'd appreciate any suggestions as to why the primer is not functioning the way it should and what other tests I can perform.

Here is a pic of the carb schematic, number 35 is the primer assembly.

Thank you for reporting this comment. Undo

It is not a good practice to ask a busy guy in the shop to give free advice....However, I suggest you buy the complete primer assembly, install it and she should work.....ET.....

    Bookmark   February 21, 2009 at 9:12PM
Thank you for reporting this comment. Undo

Thank you for your response, however, I still need to know how to remove the primer bulb retainer ring.
Also I would like to know if there may be other areas that might be the cause.
The shop was not busy and it was not like I just went in there for advice. I brought two mower blades to be sharpened.

I could understand his suggestion of changing the bowl o-ring gasket, that made sense in keeping the sytem pressurized. But changing the washer on the bowl nut made no sense because it was not leaking and a ripoff at 1.65 plus tax for such a small part.

The bowl itself was clean as could be, he suggested I change it also, I saw no reason to, so I didn't.

This morning I went out and attemted to start again, gas tank was full, manual states in cold weather below 50 degrees (in 30's), press the primer bulb 5 times holding it in after each press. Tried that didn't start, only after at least 15 pushes did it manage to start.
I myself have a nine year old Toro recycler with personal pace, similar setup, I press my primer three time and it always starts on the first pull. I can feel the differnec when pressing the primer bulb on both units. The Toro offers resistance, the Lawn Boy does not.The Toro has a Briggs not a Tecumseh on it.

Below is a pic of the identical carb setup, i found it on the net, not the best but gives you idea.

    Bookmark   February 22, 2009 at 10:45AM
Thank you for reporting this comment. Undo

Part #40 is contains the fuel orifices of which there are three - the large one across the bolt at the head, a smaller one down inside the hollow bolt and the trouble maker - a tiny one at the top of the threads that must be rodded with a soft steel wire out of a wire tie or the plain end of the appropriate wire drill size. Rod this orifice and the other small one. Blast out with carb cleaner. Use carb cleaner in your fuel for one tankful, then use Sta-Bil in your gas can every time you fill it. I also add one ounce of Marvel Mystery Oil to each gallon.

    Bookmark   February 22, 2009 at 4:02PM
Thank you for reporting this comment. Undo

I've alredy cleaned part #40 (bowl nut).
As stated the carb was like new when disassembled.
I would imagine if there was any clog in the orfices the engine would not run properly once started. This is not the case at all, the engine runs fine once it's started and continues to start on one pull when warmed.

The issue is the inability of the primer component(s) not able to deliver fuel when cold. Went into the shed and pushed primer buttons on my Toro mower, also on my chainsaw, weed wacker, hedge trimmer, they all had resistance when pressing the bulb.
Not so with this Lawn Boy Tecumseh engine.

    Bookmark   February 22, 2009 at 5:16PM
Thank you for reporting this comment. Undo

My mother's mower has the same type of primer bulb on her Tecumseh. I have never had good luck with pushing it slowly. I always give it 5 or 6 hard quick punches with the tip of my finger. This has worked for 6 years now. Try it.

    Bookmark   February 22, 2009 at 8:10PM
Thank you for reporting this comment. Undo

'The issue is the inability of the primer component(s) not able to deliver fuel when cold'

That was understood, but I thought maybe a clogged orifice could still affect priming, and most people do not even see that third orifice when they 'clean' the carb. Evidently such is not the case. It is a strange primer with no 'feel' or sound when you push it. I agree with hitting it hard and fast. If it's below 60 degrees F, I push it at least five times. Mine is a 10684 from 2004.

    Bookmark   February 22, 2009 at 8:40PM
Thank you for reporting this comment. Undo

Thanks for your replies. I've done a search on the issue and got a few ideas on how to correct.
I've ordered all the parts from Jacks Small Engines and hopefully will receive them by next weekend.

I have also learned the primer bulb rubber booth will need to be replaced since there is no way to salvage it to check the rest of the components. To remove you take a pair of pliers and twist the rubber booth out, then use a screwdriver and pry the retainer out.

I will replace the primer assemble as illustrated in part # 35, I will also replace part # 36 main nozzle tube, and part 37 ( 2 o-rings for tube).

Lastly I will replace part 30, inlet needle and seat.
This should cover all the bases and hopefully correct the problem.

I did read that these primers on these particular carbs did not feel as if they were pressurized, but pushing the primer 15 to 18 times just to get an initial sputter appears to be a problem. I did not push 15 times to begin, I started at 5 as the manual states, then would continue with 2 push increments so I would not flood the engine.

    Bookmark   February 23, 2009 at 7:17AM
Thank you for reporting this comment. Undo

'so I would not flood the engine'

Not going to happen on this engine - not with the primer bulb at least. It occurred to me that if the bulb has a pin hole/crack in it, it would still 'inflate' when you blow air into the red tube. It just wouldn't hold a vacuum, so it could not pull fuel in as it expands after being pushed. My best guess is simply a defective primer bulb. I guess we'll never know since you're going with the 'shotgun' approach and replacing everything.

    Bookmark   February 23, 2009 at 8:14AM
Thank you for reporting this comment. Undo

I like the shotgun approach description.
I just can't see spending the time to constantly remove the carb. I like doing a job once, and doing it right, if it costs a few extra bucks so be it, my time is worth something.

You're right, by changing so many components I'll never be certain of what the cause was. Who knows, even after all the new parts are installed it still might not work.
Nothing surprises me in life and the so called easy job is seldom easy.

I can absorb the 20.00 in parts if it means my 74 year old brother in-law will have no problems starting the mower.

I just hope when I reach 74 I can even remember what a mower is, never mind use it to cut grass.

    Bookmark   February 23, 2009 at 4:36PM
Thank you for reporting this comment. Undo

'I just hope when I reach 74 I can even remember what a mower is, never mind use it to cut grass.'

I hear that.

    Bookmark   February 23, 2009 at 8:45PM
Thank you for reporting this comment. Undo

Those style bulbs do not prime like the full figured ones do at their best. To prime with them, give strong
"pushes", and hold the button in for a second or two each time, play with this method until you find out how many
"pushes" works for your engine.
If you still have no luck, gently pick out the retaining
ring that holds the bulb in and remove it. Then roll up
a tiny peice of sandpaper and sand out the area where the
bottom of the bulb sits and clean it, then rub a dab of
thick grease on the bottom of the bulb and reinstall,
seating the bulb and ring with the correct size socket
to tap the retaining ring down tight.

Try this,
good luck,


    Bookmark   February 24, 2009 at 2:00AM
Thank you for reporting this comment. Undo

Thanks for the tips. The more I read, it sounds like these primer bulbs do not perform the same as others I have used.
Quite frankly it's a poor design in my opinion.

Never thought of the pick method to remove the retainer ring. I had already tapped the retainer ring down using a 3/4" deep socket but that didn't help.
Perhaps the cause is a poor seal under the bulb as you indicared, I will try to make a L shaped pick to remove the bulb.

I did order the parts but now I have my doubts they will arrive in a timely manner, or at all. I read some pretty negative reviews on how runs their business and treats their customers. Should have done my homework first or been ambitious and go to one of the local parts stores.

    Bookmark   February 24, 2009 at 7:14AM
Thank you for reporting this comment. Undo

Just wanted to post a follow up in the event others may reference this post for information.

I was able to fix the primer bulb problem.

My parts arrived and I replaced the following:
Primer Bulb Assembly (part# 35)
Main nozzle tube and O-rings (part# 37)
Inlet needle and seat (part# 30)
O-Ring for Bowl Float (part# 29)
Bowl Nut Washer (part # 44)
Gasket For Intake Pipe (part# 224)

Indeed this was probably overkill, but the bottom line is it works. After assembly I pushed the primer button and observed there was a bit more resistance, but still not the amount I am used to from other equipment employing primers.
On the first push I peered into the carb throat and did see gas coming through and I knew then it would work.
Pushed the bulb two more times and it started right up.

Just another tip I would like to mention, I read in other forums, on some engines, the outside bolt on the air cleaner housing should be screwed in for testing purposes since there is a hole that goes into the carb and you will not have pressure. This definitely did not apply to my engine; there is no hole in mine.

The main nozzle tube and O-rings looked perfect when I removed. Knowing I had the replacement parts I followed the manual in removing the bulb, use a pair of pliers and twist it out. Using this method will certainly destroy the bulb with no chance of salvaging. I suppose if I was very patient and devised some sort of L tool one could slowly pry the bulb retainer ring out.

After inspecting all removed parts I have come to the conclusion that saxman1 had it diagnosed correctly, most likely it was a "pin hole/crack in it" invisible to the human eye.

My thanks and gratitude to all that responded, hopefully the thread can help somebody else with a similar problem.

    Bookmark   February 26, 2009 at 7:11PM
Thank you for reporting this comment. Undo

Itzbinnice, I agree with your 'Shotgun' approach, (as
saxman so aptly described it), especially on carberators.
I'm surprised that after-market parts suppliers don't
offer 'kits' with all the parts included, that you had
to purchase individually. I, for one, don't want to
tear a carb apart 19 times, replacing one part at a time,
until I solved the problem. Good job, and thanks for
letting us know of your success and exactly what the
solution was.

    Bookmark   February 27, 2009 at 6:54AM
Thank you for reporting this comment. Undo

Thanks, hope the post can help others in the future.

I failed to metion that I had my doubts about based on the many poor reviews I read.
My experience was a good one, received the parts in 3 days.

After removing the bulb (tearing the crap out of it), the carb cavity where it sat in was as clean as could be, I did not need to clean it at all before putting the new parts in.
As I stated before, this unit was used one time at the most before it was given to my brother in-law.

I feel confident now he will be able to use it without issues.

    Bookmark   February 27, 2009 at 7:17AM
Thank you for reporting this comment. Undo

Congratulations on the fix. I have found Tecumseh primer bulbs to be a real pain. Many of them look alike, and vendors don't always check to make sure they sell you the right one. It can fit and look good and still not work.

    Bookmark   February 28, 2009 at 10:07AM
Thank you for reporting this comment. Undo

I made sure I had the correct part #'s and only ordered original Tecumseh parts which were identical to the old ones, upon examining with the naked eye. Only difference I found was the main nozzle tube, original was red, Tecumseh replacement was blue.

Having experience with automotive after market parts, somtemes they are not a perfect fit, can be frustrating to install. This was not the case with the parts I received.

    Bookmark   February 28, 2009 at 12:08PM
Thank you for reporting this comment. Undo

The funny thing about 'jackssmallengines' is, every time I see it I think 'jackass'. Then to find out it's true is hilarious.

    Bookmark   March 1, 2009 at 10:09AM
Thank you for reporting this comment. Undo

"The funny thing about 'jackssmallengines' is, every time I see it I think 'jackass'."

You are much more observant than I, the thought never crossed my mind, however, there must be some validity to it with all the negative stories I read. Many said they charge your credit card before shipping although the site policy states otherwise. I suppose I was just lucky ordering common parts. Not being a gambling man, any future parts purchases will be made at other sites.

Thanks for your correct diagnosis of the primer problem being the bulb itself.

I have started it three days in a row now, all with three pumps of the primer each time, it started on the first pull each time. It is cold here and is being stored in a enclosed but unheated patio. I will return to my brother in-law in the spring since he will be storing it outdoors (covered). Breaks my heart to see OPE stored outdoors exposed to the elements.

    Bookmark   March 1, 2009 at 11:40AM
Thank you for reporting this comment. Undo

First of all the Tecumseh primer bulbs I have seen all have a hole in them from the factory.

I am wondering if there is another way to overide the thing? Say you used a bulb of some type to cover the hole in the center under the destroyed prime bulb and applied your own vacuum. Or even sucked on the thing (with a hose).
Would it work?
Removing the ring has proven to me to be next to impossible. No way to wedge a screwdriver and gouge it out.
Wish I knew the "profesional" way. What did they use?

I'm told Tecumseh is now bankrupt and has quit. I guess the parts will dry up sooner than later.
So sad. But as for this primer bulb, I hope the engineer who designed it loses all his pension.

    Bookmark   March 26, 2010 at 3:36PM
Thank you for reporting this comment. Undo

OK got the %#@& thing out today. I used a nut pick. You know the kind that used to come with a nutcracker set in the kitchen. Ice pick didn't do it for me, but any scratch awl or little thicker than ice pick would prob do.

    Bookmark   March 26, 2010 at 6:24PM
Thank you for reporting this comment. Undo

"But changing the washer on the bowl nut made no sense because it was not leaking and a ripoff at 1.65 plus tax for such a small part."

It's not like it's a standard bolt or other part you can get in the bin at the corner hardware store or fabricate yourself. It's a custom-made, precision part that a dealer has to stock in inventory. To me, $1.65 is a very fair price for such an item. They could charge $4 or $5 for it and people would still have no choice but to buy it.

    Bookmark   March 28, 2010 at 8:11AM
Thank you for reporting this comment. Undo

I have a lawn boy electric start with the primer bulb up on the handle bar next to the key start. I have the bulb unit off the hose but can't get the little "press-on" nut off the nipple so I can then pull the plastic shroud off and away from the primer bulb. I have the new bulb to put on it, but can't get that little nut off. Any suggestions?
Thanks Bill

    Bookmark   August 31, 2011 at 2:57PM
Thank you for reporting this comment. Undo

I removed the retainer ring with either a metal pick tool (a small screwdriver should work equally well). I then cleaned the area to make sure there was no dirt where the bulb sits. I placed a 19MM socket over the bulb and lightly tapped it in with a rubber mallet. Good to go . . .

    Bookmark   September 1, 2011 at 5:03PM
Thank you for reporting this comment. Undo

I have this same problem with a Toro/Tecumseh except this one won't crank. I must say that this is the poorest design I have ever dealt with and I have worked on every kind of engine ever made.

My advice to anyone thinking about buying a Toro/ Tecumseh, Don't! My assessment, you couldn't give me a truckload of these junkie mowers.

    Bookmark   November 13, 2011 at 6:32PM
Thank you for reporting this comment. Undo

Could it possilby be the fuel cap that is not allowing enough air in for the carb and primer to work properly? Does the cap not have a small air hole on it somewhere?

    Bookmark   November 21, 2011 at 8:43AM
Sign Up to comment
More Discussions
Best self propelled walk behind mulching mower
Hey Guys and Gals, in the market for the best all around...
Kohler Knowledge
I am replacing my 2nd B&S 23HP engine on a Simplicity...
Charger for/charging a Toro GTS 6.75 hp
I recently acquired a several year old Toro GTS 6.75...
Lawnboy circa 1967 aquanaut/air buoy evinrude parts
Hi. I am wondering if anyone could be of assistance....
Toro Zero turn
Having trouble with Toro Time cutter ZT4200,Koehler...
Amy Bebensee
Sponsored Products
Commercial Electric Recessed Lighting 5 in. White Recessed LED Trim CER5741WH
$32.97 | Home Depot
Paisley Snow Giclee Set of Four Shades 3x6x5 (Clip-On)
$49.99 | Lamps Plus
Hunter Ceiling Fans Kensington 52 in. Indoor Bronze Ceiling Fan New Bronze 53048
Home Depot
Bronze Sloped Ceiling Adapter
$18.45 | PLFixtures
Vaxcel Orleans Nautical Outdoor Ceiling Light - 15W in. Antique Red Copper - OF2
$125.00 | Hayneedle
Arteriors Home Krista Gold Leaf Scroll Design Table Lamp
Lamps Plus
Black Copper Wall Sconce with Tiger Glass
$99.00 | Bellacor
Equinox Polished Nickel One-Light 11.38-Inch Wide Small Hall and Foyer Pendant
$133.90 | Bellacor
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™