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sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast

Push mower engine trouble

Click for full size
Illustration of carb from parts manual
I have a Bolens push mower (model 11A544L163, s/n 1k052k10693) with a Briggs and Stratton engine (model/type 10G902-0217-B1) (Manuals here.) Bought it new in 2003.

This morning I went to use it. After priming, it fired up, but died a few seconds later after the prime fuel was used. Did this several times. So I took off the filter to have a look. Nothing obvious. Pulled off this 90 degree angle rubber boot (529 in diagram) that connects the fuel line to the carburetor and cleaned it and tested it for leaks. None found - holds air pressure well. Reinstalled it and tried to fire it up again. Same results as before. Fires up, then dies a few seconds later.

So, I think to myself, I need to adjust the carb, as with any of the other power lawn equipment I have. Just one problem. As the B&S manual states: "Carburetor Adjustment: Never make adjustments to the carburetor. The carburetor was adjusted at the factory to operate efficiently under most conditions. However, if adjustments are required, see any Briggs and Stratton authorized dealer for service."

Well, now doesn't that chap your ____? It is also aggravating because the Bolens-produced manual for the mower says if it runs erratically, then adjust the carburetor.

I tried one last time to get the thing running, and it finally caught enough to continue running very roughly. I decided it was way too rough to even attempt to use it and shut it down.

There is no throttle adjustment on this thing. You just hold down the dead-man's handle before starting, priming if necessary with the push button rubber primer.

Anybody have any ideas short of finding a service place? I do not see any spring-tensioned screw like on a typical carb when looking at the actual carb or the diagram.
--
nohup rm -fr /&


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3

1 edit
If you can pull the carb make sure item 612 is clear of any blockage especially at the metering orifice and 393 is clean.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House

1 edit
reply to sempergoofy
Also make sure the diaphragm and spring are in good shape. IIRC, there is the inlet to the motor, and then the elbow connects to a pipe that runs across the motor to the exhaust to produce the pressure to push fuel into the carb to keep the motor running.

Those carbs aren't really expensive. IIRC I paid $20 for a new one. Make sure you get a new base gasket (#394) to make sure it seals. The diaphragm is part of this gasket I believe.

IIRC, there is no adjustment for these carbs except idle speed. Everything else is fixed.

--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3
said by neonhomer:

to produce the pressure to push fuel into the carb to keep the motor running.
Good point and if the fuel cap is not sealing it will not stay running.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House
I've had those motors run w/ the fuel cap off... IIRC (again) the pressure acts against the diaphragm to pull fuel out of the tank and into the chambers below the carb, and then the pickup pulls is from the chambers into the carb. The motor has to run for a few seconds to make this all work. Hence why you have to prime it.

I am not too sure about the theory of operation, but I do know it works on pressure from the exhaust and vacuum from the intake.
--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3
said by neonhomer:

I am not too sure about the theory of operation, but I do know it works on pressure from the exhaust and vacuum from the intake.
Not sure about the B&S but Honda's use crankcase pressure to do that.

However based on what you are describing the fuel cap would actually need to be vented and probably is, oops my error.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician


Jimdaboe

join:2001-01-16
Corpus Christi, TX
reply to sempergoofy
I've had the same problem. Make sure the gas in the tank is clean and has no water in it. You would be surprised how much water can get in the tank just from sitting out on hot days.


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
reply to sempergoofy
Love all the suggestions folks. It is hotter than hell outside right now and I just can't bring myself to go out again to implement and test your great suggestions until later this evening.
--
nohup rm -fr /&

bkjohnson
Premium
join:2002-05-22
Birmingham, AL
reply to sempergoofy
It doesn't sound like it is related, but is the spark plug OK?


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
said by bkjohnson:

It doesn't sound like it is related, but is the spark plug OK?
Spark plug seems to be firing for the short time (or erratic time) that fuel is present to ignite.

Dad taught me as a kid that you need three things for a lawnmower engine to run. Fuel, fire (from the spark plug), and compression. Any one of those messed up, and you have a problem.
--
nohup rm -fr /&


Pacrat
Old and Cranky
Premium,MVM
join:2001-03-10
Cortland, OH
kudos:2
Reviews:
·Time Warner Cable
Did you check the fuel tank cap vent? It's not uncommon for the pinhole in the cap to become clogged with dust/debris and engines don't run well, pulling against a vacuum. Sounds like the carb is okay, but fuel isn't getting into the carb, even though all the filters and tubes have been checked and appear to be clear.
--
I was born at night... but not last night!


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
I just tested the fuel cap. It has three small holes in it. The cardboard-like gasket liner inside the cap has four holes. I was able to blow air through the three holes. Still dying after the prime gas is consumed. I also tried it with a the cap loosened (almost removed but askew).

Sunday morning I'll start taking things apart and pull the carb if I can.
--
nohup rm -fr /&


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
reply to sempergoofy
i have a similar bolens i bought in 2005. mine started this same thing ealier in teh year. if it is the same problem as mine was you need to go get some seafoam and put it in your gas, the carb is dirty. i also sprayed carb cleaner in the carb, but the seafoam is what did the trick as my cleaner was not getting in the oricifices.

you cna thank the wonderful EPA for the nonadjustable carbs, just the first step in their plan to cut small engine emissions.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


AOLBites

join:2002-11-10
Lakewood, OH

2 edits
reply to sempergoofy
The second video is more informative for your problem

»www.youtube.com/watch?v=eUa3paHh···nel_page


»www.youtube.com/watch?v=ZIZg8myJ···=channel

--
(sig was too long)


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast

1 edit
reply to sempergoofy
Click for full size
A little carbon visible here (sorry, blurry)
Click for full size
Choke looks clean
Click for full size
View from above where filter attaches.
Click for full size
View from bottom. Diaphram protrusion visible.
A short update. I tried some Sea Foam and carb spray today. No progress. It still fires up from the fuel (or Sea Foam if dripped into the carburetor) and runs a few seconds sounding good until that fuel is gone.

So I just pulled the carburetor out. Had to drop the fuel tank, too, to accomplish the removal. It was easy though. The carb has dirt and grime on the outside of it, but the inside looks fairly clean. Some carbon buildup visible when the choke is open (blurry pic). It was getting too dark to continue outside, so I have put it away for the evening and will pick up tomorrow evening.

The spring in the diaphram mentioned above seems to spring ok if I touch it and release it.

If I can find this carb at H.D., Lowes, or a local hardware store as cheaply as discussed above, that may just be worth it because I sure do not see anything obviously wrong here yet.
--
nohup rm -fr /&


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
reply to sempergoofy
you need to mix the seafoam in the gas at the recommended rate and run a tank thru it. if it does like mine, once the engine warms up it will begin to suck gas on it's own and stay running. the small orifices in there won't get any cleaner in them when you dribble it down the throat. it could also be the diapragm itself is just stiff from drying out.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


zen1

@optonline.net
reply to sempergoofy
a passage is blocked, you can try putting the carb in a metal bucket, and covering it completely with seafoam,(remove that black gasket) and let it sit at least overnight(longer is better) sometimes doing that clears out the passageways.


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
reply to davidg
said by davidg:

you need to mix the seafoam in the gas at the recommended rate and run a tank thru it. if it does like mine, once the engine warms up it will begin to suck gas on it's own and stay running. the small orifices in there won't get any cleaner in them when you dribble it down the throat. it could also be the diapragm itself is just stiff from drying out.
Ok. I did read the directions and ratios and attempted to achiive that proportion with the gas in the tank. After six iterations of prime-start-die plus three of Sea Foam directly into the carb and spraying the external linkages with cleaner I figured it wasn't going to cut it. I can reinstall and try harder and see if I can get it to run on its own again as I did that one time described in the thread opener.
--
nohup rm -fr /&


Jan Janowski
Premium
join:2000-06-18
Skokie, IL

3 edits
reply to sempergoofy
Clogged jet in carb.

Put STABIL in your gascan regularly

Replace gasgets... (394)


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
reply to sempergoofy
i may have missed it, but is the gas FRESH? ethanol blends go bad quicker than older unleaded did.

since you have the carb off, soak it in a bowl of straight seafoam overnight. this will help to loosen up the junk.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
Filled my 1 gallon gas can up at the station a few weeks ago. The gas in the mower tank has been replenished twice from that supply since buying the gas. (So has my riding mower.) I ran it dry before storing it over the winter. Used it several times since spring for the small amount of pushing I have to do. I don't think it is a fuel freshness issue since when it is primed and fires up, it sounds normal (smooth running) until it dies after that fuel from the prime is consumed (some number of seconds). The one time Saturday that I got it continue running was the only time it ran roughly.
--
nohup rm -fr /&


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
sure sounds exactly like mine. i would tie a strap on the deadman to keep it running, then every time it tried to die hit the primer button a time or two. after a minute or so it would run rough, then eventually smooth out.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
I put the carburetor into a Sea Foam bath shortly ago. I'll see about reinstalling and running some Sea Foam mixed gas as suggested.

I checked Home Depot at lunch. They do not appear to carry carburetors in their parts display (filters, belts, blades, wheels, keys, they do). Pretty sure I saw one at the h.w. store recently but did not get over there (yet).
--
nohup rm -fr /&


sempergoofy
Premium
join:2001-07-06
Smyrna, GA
Reviews:
·AT&T Southeast
reply to davidg
Success!

After letting the carburetor soak 2.5 hours, I shook it out and dried it off. Reinstalled the gas tank and carburetor. Fueled the tank about 1/4 full. Primed, cranked and got the same results as before. Using davidg See Profile's advice, I primed then cranked it again and kept hitting the primer bulb when it was about to die (which was every few seconds). The deadman's switch was tied down so that I did not have to keep holding it. Once it got hot enough, the engine was able to sustain itself while running very roughly. I then added a little bit of Sea Foam to the gas tank. It continued to run roughly for a few minutes, and then suddenly, normally.

I let it run for about 10 minutes. After shutting it down, I cranked it once more while the engine was hot and it started right up and ran normally. The air outside is still too hot for a sane person to push a mower around the yard. I hope to get back out in just a bit to do the small amount of trimming I need to do. Hopefully a cold start will be normal this time.

Thanks all for your suggestions, especially davidg See Profile.
--
nohup rm -fr /&