Small Engines (Lawn Mowers, etc.)/Suzuki ac4000gd2e generator


Motor runs continuously until choke is pushed back to closed position. I have used numerous times with the choke held open but while replacing plug &fuel filter noticed the spark plug was quite black. I have been told the carberator may need to be rebuilt due to gum up of old fuel? Have run sea foam additive but still requires choke. Please advise?

A black spark plug indicates the engine is running rich, too much fuel or not enough air.

The engine should run with the choke open, this is how all gas engines should run.  It does sound like something is wrong with the fuel system and the most common problem are dirty carburetors.

I would remove, dis-assemble and clean the carb.  Blow compressed air from an air compressor through all the carb orifices and then spray each hole with carb clean.  Blow air through all the holes again.  Re-install and see if it runs better.


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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