Briggs 8hp backfires thru carb ?

[Sean McGillicuddy]

My Briggs 8hp engine will not start.
It backfires thru the carb.
I've taken the head of and cleaned it well, valves looked great no sticking
Do you think it could be the flywheel key?
I'm doing a carb overhaul since it's down.
Thanks

 

[VirginiaIron]

Either the intake valve isn't seating properly or the timing could be off. I have seen many a small engines out of time due to a bad/damaged key.

 

[Corey]

How did it get to the 'no start' condition? If it is some piece of equipment which came to an abrupt stop / lock-up, then it's likely the flywheel key sheared. If it started slowly deteriorating, then I'd look more toward the intake valve, broken valve spring, failing keeper, etc.

 

[Sean McGillicuddy]

It was the flywheel key !
All back together .. started first pull ... Boy I didn't think it was running that bad.. cuts better @ slower engine speed..

 

[VirginiaIron]

It was the flywheel key !
All back together .. started first pull ... Boy I didn't think it was running that bad.. cuts better @ slower engine speed..

I reckon the nut loosens or was never properly torqued. Sometimes a single backfire will cause key damage.