Converting Coil type ignition to MAG
Posted: Fri Apr 08, 2016 1:40 pm
Below is what was originally posted on the old IH registry on converting from ignition coil ( Onan )to a magneto ignition ( Kohler Magnum ).
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Part number 725-1375, "relay" is an active Cub Cadet part used on many of the cyclops tractors and located near the voltage indicator on the battery tray
Relay for Mag Engine conversion.
I used an automotive relay that Travis had laying around his garage one day I was up there..a typical "here use this one" deal....it worked and was free, but I don't know where it came from, sorry.
Pins 85 and 86 are the low current switch loop, when current from the KT style ignition switch is applied, they close and in turn close the contacts on pins 30 and 87, the high current side of the relay....BUT 87 isn't used so they do nothing and the engine runs on the mag ignition. When current is removed from the low side of the relay, contacts 30 and 87 open, closing 30 and 87A (basically the high side toggles between 30/87 energized and 30/87A de-energized). So, if you ground 87A, when the current from the old KT style ignition switch is off, the relay opens and contacts 30 and 87A close on the "back-side" grounding out the mag and killing the engine.
Find a relay with continuity between 30 and 87A with no wires hooked up to it and you should be in the clear.
Caution!!!!!! Test the system with a test light or meter BEFORE hooking the mag to the relay (pin 30). No need to ruin a +$50 mag bacause something isn't wired right, and I'm told mags don't like 12v applied to the kill wire under certain situations.
According to Todd Markle, The NAPA # is AR204
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Part number 725-1375, "relay" is an active Cub Cadet part used on many of the cyclops tractors and located near the voltage indicator on the battery tray
Relay for Mag Engine conversion.
I used an automotive relay that Travis had laying around his garage one day I was up there..a typical "here use this one" deal....it worked and was free, but I don't know where it came from, sorry.
Pins 85 and 86 are the low current switch loop, when current from the KT style ignition switch is applied, they close and in turn close the contacts on pins 30 and 87, the high current side of the relay....BUT 87 isn't used so they do nothing and the engine runs on the mag ignition. When current is removed from the low side of the relay, contacts 30 and 87 open, closing 30 and 87A (basically the high side toggles between 30/87 energized and 30/87A de-energized). So, if you ground 87A, when the current from the old KT style ignition switch is off, the relay opens and contacts 30 and 87A close on the "back-side" grounding out the mag and killing the engine.
Find a relay with continuity between 30 and 87A with no wires hooked up to it and you should be in the clear.
Caution!!!!!! Test the system with a test light or meter BEFORE hooking the mag to the relay (pin 30). No need to ruin a +$50 mag bacause something isn't wired right, and I'm told mags don't like 12v applied to the kill wire under certain situations.
According to Todd Markle, The NAPA # is AR204