Small Engines (Lawn Mowers, etc.)/B&S engine won't start



B&S 92502 3186 01 Magnetron. Lawnmower. The mower was in the cellar for the winter. When I first took it outside it wouldn't start until I pulled the plug and put an eyedropper of gasoline in. Put the plug back in and the mower started and ran about 15 minutes, until it ran out of gas. This was gas left from last fall.

I refilled it, and from that point on, it will not start. If I put a bit of gasoline in the plug hole, it will start, but only runs a few seconds then stops.

I made sure the gas tank was empty and dry, then filled it about half way with fresh gasoling I just bought. Same thing. Only starts when I put a little has in the plug hole and runs a few seconds.

If this is caused by the old gas that sat in the engine all winter, why would it have run for 15 minutes until it ran out of gas, but won't run now? Does the carburetor need cleaning, or would adding a gas stablizer now clean it? If not, is there anything that would clean it just by adding something to the gas?

Most likely you will need to replace the carburetor diaphragm.

You have a Briggs and Stratton pulsa-jet carburetor.

Here is a You Tube video:

Those carburetors tend to warp but you can level them again with a flat file but you have to remove the fuel pick-up tubes to file the bottom of the carb.


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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