Small Engines (Lawn Mowers, etc.)/Wiring


I recently bought a 2005 troy bilt lawn tractor from my cousin. The  numbers for the engine are;  Briggs and Stratton Model 31C707 Type 0154-E1 code 0508227E. The wiring was a mess so I tore it all out and proceeded to jury rig wire it.  I have the coil wired to a toggle switch, the solenoid and starter wired to a push button.  It will crank up and run good.  I found 2 wires coming out from under the flywheel.  One is red and the other is black I think.  I was told this is for charging the battery and lights.  I don't know how to  wire these 2 wires up the right way.  Does this motor have a regulator?  If so how do I proceed to find it and wire it up to the battery and lights?  Can I just run the red wire to another toggle switch and then to the batter and turn it on while mowing?  Will this charge the battery without damaging anything.  Also, I've notice the carb solenoid doesn't click anymore when charged.  Can it be removed without taking the whole carb off?  Any way you can help me finish this job will, I will be very grateful.  Thanks, Dinl

First you need to identify which alternator system you have.  Use the link below (page 15):

You may have to scrape the wire insulation a little if there is paint on the wire insulation...then you can tell the correct color of wire(s) your charging system has.


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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