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Small Engines (Lawn Mowers, etc.)/Briggs and Stratton Carb question


Hello, I have a Briggs & Stratton (Intek 22-hp) 407777-0131-E1, 990603YG with a Nikki carburetor. I bought this engine used. It has backfired through the intake at idle from the day I installed it. I cleaned the carb, replaced jets, cleaned again and again. I have checked and adjusted the valve tolerance several times and nothing helps. I finally bought a new carb based off everything I can find online. Well the kit says some engines require the restriction plate, some dont. I have no idea how to know if mine requires one. I dont have one now, but that doesnt mean anything because Im un-aware of the history and previous owner actions and maintenance. Is there any way you can answer that question for me?

I have not seen any of those engines with a restriction plate.

Do you any wires that connect to a solenoid on your carburetor?

Is you engine running hot by chance?

Over the years, grass, dirt and other debris can accumulate on the engine cylinder fins, under the flywheel and all over the engine.

If you use engine degreaser to break down the grease/dirt and wash the engine clean with water it might make it run cooler.

The backfire could also be cause by a lean carb mix or intake leak.  Are all the intake gasket in good shape and sealing?

What are your valve adjusted at?

Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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