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View Full Version : 11HP Briggs and Stratton, gas blowing out the carb!


oilstain
Apr 14, 2009, 10:31 AM
I've got a Briggs and Stratton 11 HP L head (horizontal) on a mower I'm trying to fix.

When I check the valve clearance at 1/4" past TDC I have the correct clearance .007 (aluminum block), however, during the ENTIRE compression stroke, the intake valve is open a few hundreths and it's blowing the fuel out of the carb. How could this possibly work? How could the engine ever NOT blow its combustion mixture out of the carb?

I've heard of a easy-start system that releases the compression when rpms are low (during crank) but I'm not sure if this engine has that. I pulled it off the mower and opened up the bottom end, and I don't see any mechanism in there that would do any such thing. Also, I thought those mechanisms worked on the exhaust valve. Anyway, on the cam, I only see the two regular lobes.

I've checked to make sure the flywheel key is in good shape, and the two dots on the cam are lined up the way they should be.

HELP, I don't know where to go from here!

Model 252707 Type 0621-05 Code 91081611.

1983nab
Apr 15, 2009, 08:04 PM
It sounds like the inlet needle in the carburetor is Letting too much fuel go though
Try rebuilding the carb

oilstain
Apr 20, 2009, 07:08 AM
it sounds like the inlet needle in the carburetor is Letting to much fuel go though
try rebuilding the carb

Done and done, that's what did it. Weird though, that the intake valve simply stays open (just a little) during the compression stroke.