953 nut 51,381 #1 Posted March 4, 2020 There have been several questions asked on RedSquare about replacing a Battery Ignition "K" engine with a Magnum engine. On a battery ignition equipped Wheel Horse if the PTO is on the seat switch closes to allow power to the points when you are in it and opens when you get up removing power from the ignition coil. With a magneto ignition system, the seat switch is open when you are in the seat allowing the magneto to operate and will close when you get up causing the magneto to ground killing the engine. To convert from a battery ignition to magneto, you could change the ignition switch and seat switch or you could use a relay. The installation of a “kill relay” would be an easy fix if you are comfortable with electrical work. You can pick up a five-pin relay and socket at any auto parts store and wire it in. Terminal 85 or 86 would be connected to the wire that went to the ignition coil and the other to ground. When you turn on the ignition switch this will magnetize the coil and activate the switch in the relay. Terminal 87a will go to the magneto on the engine (the kill wire) and terminal 30 will be grounded. When the key is off the 87a/30 will be grounding the magneto preventing it from running, when the key is on the flow of electricity through 85/86 will open it up and allow the magneto to work. Your safety switches will continue to protect you and the cost of the relay and socket is less than $ 10.00. Hope this helps. 2 6 Share this post Link to post Share on other sites
clueless 2,898 #2 Posted March 4, 2020 3 hours ago, 953 nut said: There have been several questions asked on RedSquare about replacing a Battery Ignition "K" engine with a Magnum engine. On a battery ignition equipped Wheel Horse if the PTO is on the seat switch closes to allow power to the points when you are in it and opens when you get up removing power from the ignition coil. With a magneto ignition system, the seat switch is open when you are in the seat allowing the magneto to operate and will close when you get up causing the magneto to ground killing the engine. To convert from a battery ignition to magneto, you could change the ignition switch and seat switch or you could use a relay. The installation of a “kill relay” would be an easy fix if you are comfortable with electrical work. You can pick up a five-pin relay and socket at any auto parts store and wire it in. Terminal 85 or 86 would be connected to the wire that went to the ignition coil and the other to ground. When you turn on the ignition switch this will magnetize the coil and activate the switch in the relay. Terminal 87a will go to the magneto on the engine (the kill wire) and terminal 30 will be grounded. When the key is off the 87a/30 will be grounding the magneto preventing it from running, when the key is on the flow of electricity through 85/86 will open it up and allow the magneto to work. Your safety switches will continue to protect you and the cost of the relay and socket is less than $ 10.00. Hope this helps. So can I ground 30 and 86 on the relay together, and eliminate 87? Even simple electrical stuff sometimes confuses me. Share this post Link to post Share on other sites
953 nut 51,381 #3 Posted March 4, 2020 3 hours ago, clueless said: can I ground 30 and 86 on the relay together, and eliminate 87? Yes, one ground wire could be used for both. Terminal 87 is not used for this application. One reason this works well is that the safety switches on battery ignition systems are in parallel and feed power from the ignition switch under the proper conditions. With magneto systems they are in series and remove grounding from the Magneto/trigger module so the engine can run if the proper conditions have been met. I am developing a thread about safety switches that I hope will clarify this muddy subject. 1 Share this post Link to post Share on other sites
jeffcraddoc@yahoo.com 2 #4 Posted July 28, 2021 thank you for your replies i really appreciate them. 1 Share this post Link to post Share on other sites
peter lena 8,031 #5 Posted July 31, 2021 @jeffcraddoc@yahoo.com done that on my horses , never look back , instant starts , also add battery cable from engine frame area to battery ground rail mount , for enhanced grounding , good luck , pete Share this post Link to post Share on other sites
Anvil 6 #6 Posted February 9 Hello 953 nut, Thank you for your outstanding advice and description of making the M20 work where the P220 has been. I have greater concerns with the WH PTO connecting to the crank. I believe the original Huskee drove the main belt for everything off the flywheel side of the crank. I do not know what is on the other end. At one time I had a WH with a Kohler KT-17 so I began looking into crank shafts and what the WH drive end of the crank looks like (specifications). I'm not having much luck. I would hate to drop good money on this old Huskee and find I can't connect the WH PTO to it in the same way. They don't make it easy. Anvil 1 Share this post Link to post Share on other sites
