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Small Engines (Lawn Mowers, etc.)/Briggs and Stratton P317770348e1


I have pretty much rebuilt my lawn tractor engine, a brigg and Stratton p31777.  I have replaced the fuel pump,fuel filter, ignition magneto, air filter, fuel needle valve, gaskets, head assembly (due to a bent pushrod and hole through the head, made sure the cam and shaft were line up with the dots, new spark plug and valve clearance set correctly, I believe, and unfortunately the engine still will not start.
It wants to, but fires like once or twice and then just cranks.  Lots of fuel smell, and fuel coming out of the exhaust.  
Is it possible the needle valve is stuck, or the valves are not adjusted correctly?

It could be the valves, the inlet needle or even the flywheel key could be sheared.

Did you follow the procedures detailed on the Briggs website?

You Tube video:
FYI, I use a drinking or WD-40 straw to feel the piston comes up to top-dead-center on the COMPRESSION stroke.

Did you check the flywheel key?

Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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