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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 28645
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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Curtis I have a Briggs 210000 11HP generator motor with a

Customer Question

hey CurtisI have a Briggs 210000 11HP generator motor with a nasty backfire issue
Submitted: 2 years ago.
Category: Small Engine
Customer: replied 2 years ago.
The engine starts fine; attempts to come up to the preset RPMs. As the RPMs increase it starts backfiring into the carb. The backfiring is violent and inhibits the RPMs from achieving the correct level.This behavior is very consistent.
Expert:  Curtis B. replied 2 years ago.

Have you tried adjusting the valves?

Expert:  Curtis B. replied 2 years ago.

Could the exhaust be restricted?

Customer: replied 2 years ago.
New Plug, adjusted ValuesInteresting idea on the exhaust restriction ------One other item; it appears to be running very rich
Expert:  Curtis B. replied 2 years ago.

Check the exhaust, I assume you have had carburetor off? And float and beedle are good.

Expert:  Curtis B. replied 2 years ago.

needle

Customer: replied 2 years ago.
I had the carb off all looks good --- clean
Expert:  Curtis B. replied 2 years ago.

OK

Customer: replied 2 years ago.
could it be a compression release issue on the cam?
Expert:  Curtis B. replied 2 years ago.

NO, it would only affect starting.

Customer: replied 2 years ago.
any other ideas?
Expert:  Curtis B. replied 2 years ago.

backfiring is sign of restricted exhaust or out of time, where valves are open when spark occurs. Next would be to check the flywheel timing key.

Customer: replied 2 years ago.
ok --- good thoughts --- timing & restricted exhaust
I will check these and come back to you.
Thanks
Expert:  Curtis B. replied 2 years ago.

let me know!

Customer: replied 2 years ago.
Morning CurtisI have gotten back to this generator ----- I believe it is a cam issue. The lift and duration of the exhaust value is far less than the intake.I did check the fly wheel key, no issues there.
Expert:  Curtis B. replied 2 years ago.

Worn cam not common. Did you reset the valve lash?