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Small Engines (Lawn Mowers, etc.)/Briggs 16.5 twin carb problem


I'am working on a mower for a friend of mine he said it has not run for the last three years.I drained the old fuel pulled the fuel line flushed it with fresh gas pulled the top off the carb cleaned it all out cleaned the jets sprayed out all the passages with carb cleaner blew it all out with compressed air reassembeled everything and put in about a half gallon of fuel got it to start but wants to run wide open but the throttle butterfly is at idle position will run slower but only with the choke almost closed throttle plate position doesn't change rpm in any position used carb cleaner looking for any vacuum leaks but nothing the owner said it run fine when he stopped using it and got his new one. i'm baffeled, did i overlook something?

Did you download the service manual?

Is the governor spring installed?  Is the governor adjusted properly?  Just Google "Briggs and Stratton governor adjust" to locate the governor adjust procedures.

Can you control the engine speed if you manually move the carburetor butterfly shaft by hand?


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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