1 crank

[robert32479]

Briggs and Stratton will only do 1 rotate on the flywheel and then hum. I got new plug, ignition coil, filters, oil. When I put my hand over the air intake it get a couple cranks.

 

[Hammermechanicman]

Bad compression release or too much valve lash. Humming is the starter motor melting down.
What is the motor model numbers

 

[Rivets]

Cylinder filled with gas is my guess. Remove the spark plugs and put a rag in front of each spark plug hole. I’ll bet you see fuel flying out. Solution, remove carb and rebuild, as the float needle and seat are not working together properly and need to be replaced. Change oil, as it is contaminated by fuel. When it starts up make sure you are out side because it will smoke like made for a bit. Might even have fuel in the muffler.

 

[robert32479]

Model 331877-2371-g5.

 

[robert32479]

I changed the plug before and the oil and tried a new carb

 

[robert32479]

When I take the air filter off and cover the air intake with my hand I get good cranks till I take my hand off. But never fires up