Briggs and stratton model 33R877003-G1 will only run with air intake almost all the way covered

[ohiobob]

I have a craftsman rider with a BS engine 33R877003-G1 that just stopped running while mowing. When I try to start it it just cranks but I can cover the air intake tube and it will start but when I remove my hand it dies.It is like its getting to much air.I covered the intake with tape and it ran for awhile.It I readjusted the valves cleaned the carb.Thanks for any help you can give me.

 

[sgkent]

check the fuel level and supply. Sounds like it is out of fuel, or something is obstructing the fuel supply to it. Loosen the tank cap, wait 5 minutes and see if that helps any.

 

[ohiobob]

I have checked the fuel supply everything is good. Someone else said it could be a plugged beather on th engine.

 

[DaveTN]

Just having available fuel supply from the tank to the carb
doesn't mean the carb is actually working efficiently. I would
disassemble the carb and boil it out with some solution and
try again. Sounds like "fuel starvation" even tho fuel is there.
Just not able to use it. Welcome to the LMF!

 

[ohiobob]

Thanks I'll try that and let you know.

 

[bertsmobile1]

If it only runs with the air supply almost blocked off then you have one of 2 problems
1) not enough fuel getting in to make a combustable air:fuel ratio .
2) air entering after the carb diluting the air:fuel ratio

So start with saturating the area between the carb & the engine with WD40 while the engine is running
Work the governor so the engine revs up and backs off
Clouds of white smoke = air leak

After that remove the carb and clean it

 

[ohiobob]

If it only runs with the air supply almost blocked off then you have one of 2 problems
1) not enough fuel getting in to make a combustable air:fuel ratio .
2) air entering after the carb diluting the air:fuel ratio

So start with saturating the area between the carb & the engine with WD40 while the engine is running
Work the governor so the engine revs up and backs off
Clouds of white smoke = air leak

After that remove the carb and clean it

Thanks I'll try to get to run long enough to do that.

 

[ohiobob]

If it only runs with the air supply almost blocked off then you have one of 2 problems
1) not enough fuel getting in to make a combustable air:fuel ratio .
2) air entering after the carb diluting the air:fuel ratio

So start with saturating the area between the carb & the engine with WD40 while the engine is running
Work the governor so the engine revs up and backs off
Clouds of white smoke = air leak

After that remove the carb and clean it

I did that today and no white smoke took carb apart cleaned it even ran small wire thru ports its still doing the same thing. I'm lost never had anything like this.

 

[bertsmobile1]

I did that today and no white smoke took carb apart cleaned it even ran small wire thru ports its still doing the same thing. I'm lost never had anything like this.

OK we have ruled out a massive air leak at the carb or manifold
did you clean it according to the instructions at outdoor power info if not then it is not clean
Pull the blower housing off and have a good look at the head gasket joint for signs of leakage ( wet or exhaust stains )
If you have a can of carb cleaner, start the engine then spray SHORT shots of carb cleaner down the carb throat.
Note the engine will knock a bit when you do this but don't worry about that.
If it will run for about a minute with continual short shots of carb cleaner then that suggest a fuel supply problem
Check that the carb solenoid plunger retracts fully when the key is in the on position .
If it is a 2 wire solenoid flick it around and make sure it stays retracted .

Let us know how you go

 

[sgkent]

if the air filter were clogged, it would make the fuel mixture too rich. His issue is the opposite, the mixture is too lean. Although not directly related, I had a set external metering jet unscrew and fall off an edger carb. It only ran when I choked it because of the air leak it caused. I would look closely at the carb, hoses etc., to be sure nothing is missing. That said, if choking the engine by putting their hand over the carb makes it run, then the problem is too lean a mixture, the goal has to be finding the cause of that. It can include bad fuel hose, filter, some defect in the carb, defect in a fuel pump if there is one, cracked manifold, loose manifold, crack in a head, blown head gasket, etc.. Anything that can affect the air to fuel ratio by either letting in too much air or too little fuel. Just choking the carb can cause enough vacuum to pull lots of fuel in. That compensates for not enough fuel or too much air. I do it all the time when running my leaf blower dry of fuel. I drain the tank and it runs off the fumes in the tank, fuel in the hose, and crankcase for about a minute. Then it starts to stumble as it runs out of fuel so I choke it, and it runs another 30 seconds or so because I am artificially affecting the air to fuel mixture. A hand over the carb makes the mixture richer.