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Donald, Small Engine Technician
Category: Small Engine
Satisfied Customers: 2146
Experience:  I have 25+ years of experience repairing 2 & 4 cycle engines
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I have a 12 HP Briggs I/C vertical lawn tractor engine that

Customer Question

I have a 12 HP Briggs I/C vertical lawn tractor engine that wouldn't start. Replaced the coil and it starts but won't rap up firing every fourth time. The flywheel pin looks straight and correct. The valves have blow back through the carburator though. What can I do to fix it.
It was a replaced engine originally had a 24 HP Twin and the seller swapped for this old 12 HP Briggs and kept the 24 HP twin. It has ran for the last two years since I got it used on the classifieds. Junk?
Submitted: 2 years ago.
Category: Small Engine
Expert:  Donald replied 2 years ago.

Hello. My name is***** will be happy to assist you. Have you checked your valve clearances? The backfiring through your carburetor, is very likely caused by either your valves not properly seating, or because your valve clearances need to be properly set.

Expert:  Donald replied 2 years ago.

Before junking your engine, I would consider doing a valve job.