Small Engines (Lawn Mowers, etc.)/B&S 18hp L-head twin


Hello Eric,

I just got an 18hp opposed twin which sure looks like an Onan boxer engine except the cast iron block. Everything appears to OK, I can just imagine you know where most this engine troubles are. I would appreciate you sharing what the high-failure items are and what to be watching out for.

I'm planning on a propane/gasoline conversion is this engine a good candidate? Thanks retired computer E.T.

Is your setup to run on one type of fuel?  I have seen conversions but usually the conversion only allows one fuel type.

How old is the engine and what do you plan on using it for?  You can tell the engine age by looking at the first two digits of the code number.  As for the application, I have seen L head twins in everything from riding mowers, generators, pumps to go-karts.  


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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