Small Engines (Lawn Mowers, etc.)/Electtical Wiring JD RX75


QUESTION: I am attempting to restore repair a JD RX 75 #MORX75X022463 with a Briggs 12HP 284707-1026-E. If I splice the connectors from the stator on the Briggs engine to the white and black wires from the harness of the old Kawasaki engine the charging system and everything should work correctly? The Briggs is a dual circuit 3A, the Kawasaki engine was FC290V original engine.

ANSWER: Did you refer to the manual at the address below:

Use the manual to identify your alternator on the Briggs engine.

Use this link for the Kawasaki manual:

The two manuals should be very helpful.  How many wires come out of the Kawasaki alternator?  One or two wire?


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QUESTION: I have looked at both manuals in those links before asking my original question.

There are only two wires from the old Kawasaki black and white.

The Briggs is black and red and my thoughts are that from the wiring diagram in the briggs alternator book it will connect directly.

ANSWER: I suspect it is a direct connect as well but my only concern is the rectifier (diode).  Do you know if the Kawasaki engine alternator rectifier (diode) was in the engine alternator harness or the mower wire harness?  It should not really matter where the diode was located as the effect is the same based on the fact that charging the battery requires positive current (electron flow theory) and all the charging systems maintain the same polarity.  In simple terms the diode(s) will be installed for the proper polarity.

Do you have a volt/ohm meter?  What color are the wire on the mower frame that used to connect to the Kawasaki engine?  Can you trace these wires back to the ignition switch?


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QUESTION: I can't trace the wire to the ignition switch without unraveling the entire harness.

I do have a volt/ohm meter. The wires from the Mower frame that connected to the Kawasaki are black and white. The white has a connector (white) or diode in the middle then goes to the igniter and then into the engine. The black wire goes straight from the harness to engine no breaks.

I found this wiring diagam:

I would use an ohm meter and verify the black wire connects to the ignition switch.  If you unplug the igntion switch you should be able to measure zero ohms from the switch plug marked "B", should be a red wire, and the black wire on the connector.  

Is the Briggs engine to a point where you can start it?

Use this link and tell me what alternator the Briggs has:

I suspect you have a Dual circuit Alternator part number 696459.  If so, the Briggs red wire should connect to the batter to charge the battery on the mower.  The red wire has a diode (rectifer) to covert the AC to DC for charging the battery.  The black wire on the Briggs if AC for running AC lights.

Does the RX75 have an AC light?  Can you attach a picture of the wire connector of the JD mower?  It's been many, many years since I saw that mower and don't remember much about the wiring.


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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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