14.5hp Briggs and Stratton OHV - 287707 Engine Mode - Gas in Oil -

Ok guys - I'm Stumped

I have gas in the oil. It runs for 15 seconds, then stalls in a cloud of smoke.

I read the forums and thought it was:
1) Carburetor problems - I checked the carburetor and the float is fine - it rises and falls with the gas level. The carburetor is clean, not gummed up at all. There is no excess gas in the carburetor, and the air cleaner is dry - no oil or gas in the air cleaner
2) Cranckase recirc vavle - it seems to operate fine -sucked on the hose and it draws into the air breather chamber fine.
3) Head Gasket - Head gasket is in perfect condition - no breaks or cracks.
4) Compression - the compression seems good- hard to turn over the engine by twisting the "fan" cover by hand

Last time I used it it was hesitating (misfiring). This time it only ran 10 min before stalling as described above

So now I can't figure out what was wrong. Any help would be appreciated Thx

Need to replace needle and seat in carb.
Luck

Hi,
You have done an admirable job of supplying the info. Could well be the needle and seat. You have not said the machine brand. If the fuel tank is in the rear, it is likely that it has a fuel pump and that the diaphragm in it has failed. It is usually on the left rear corner of the engine, black plastic and has three hoses connectede to it. One goes to the carb, one to the fuel tank and one to some location on the sump where it has contact to the pressure pulses present there. A hole in it will allow the engine vacuum to pull fuel into the sump.
Peace,
Clarke

This is a Walbro carburetor - the seat seems to be pressed in. Doesn't
Pull out with needle nose pliers

How do I get it out? I've got a new seat, but don't really want to drill out the old one.

Al

OK - so I replaced the seat and needle valve. Had to pull the seat out with a bolt threaded in and tap the new one in.

BUT still same problem - not as bad as before, but then I probably haven't got that much gas in the oil yet after running 5 minutes. Machine idles fine, but start cutting grass and in 1 minute it begins to sputter, then more and more until stalling. Then runs again but stalls when the blades are turned on. Idles fine, low or high revs.

This is a SABRE tractor 14.5HP Just one gas line from tank to carb and Walbro carb has a solenoid shut-off. Any more ideas guys? - thanks again

Al

Hello did you ever find out what the problem was?