I have a Briggs and Stratton 21HP V engine. Cleaned carburettor replaced seals, checked float and needle, checked fuel cut off solenoid (it works). Checked compression and found 175 lb/sq" both cylinders. Engine runs smoothly with lots of power. I am totally baffled as to how the gas gets in while I am running. Does not get in when not running. Appreciate any ideas.
Post tractor model number from under seat as well as all numbers from engine data plate, thanks. You need to purchase correct B&S carburetor overhaul kit, clean & install new kit or purchase new carburetor. Some kits are almost as much as new carburetor.
It was the fuel pump. Replaced it and no more problems. Gas goes down the tube connecting pump to the crankcase if the fuel pump diaphragm is perished.
