Briggs 6.5 hp knocks 3 or 4 times on start up, then sounds and runs fine

[mystic240]

Daughters mower. Can not figure this out. Flywheel key ok, blade key good. Has oil in crankcase. I removed the bottom crankcase and checked the rod, it is tight and good. No play in the main brgs. What am I missing?

 

[darrinster]

Try with the blade off. Also if you can record a video of it starting and running might help others diagnose the problem.