Deere GT262 w/ Kawasaki FC540V-JS00. Bypassed igniton switch and now blowing ignition coils

[KyleM81]

Hi folks,
I have an older John Deere GT262 with the Kawasaki FC540V. The circuit board in the ignition switch went bad so I rewired the whole tractor using a generic keyed igniton switch from Autozone, and then bypassed all the safety switches as well as the PTO to work with generic toggle switches. The problem im having is that it will turn on and run great, but when i turn it off it blows the ignition coil and wont restart. I replaced the igntion coil and the same thing happened. I started it up and drove it around and then turned it off again and the ignition coil blew again. Was there some sort of resistor in the circuit board that I need to add to the ground wire that goes to the coil? Any other ideas? Thanks in advance....

 

[txmowman]

Hi, Is power applied to the ignition coil ground circuit. This would damage the diode internal to the coil potentially. Is there no spark when you go to restart, is that what you mean by "blows the ignition coil"? Or, what is happening to give the impression that it is at key off? My initial thought is that the configuration of the key switch is not the same as the original.

 

[KyleM81]

Hi, Is power applied to the ignition coil ground circuit. This would damage the diode internal to the coil potentially. Is there no spark when you go to restart, is that what you mean by "blows the ignition coil"? Or, what is happening to give the impression that it is at key off? My initial thought is that the configuration of the key switch is not the same as the original.

No there is no power to ignition coil. I have it configured that when I turn the key off it grounds the coil to shut it down.
Correct there is no spark after I turn it off the first time and then try to restart it.

 

[txmowman]

No there is no power to ignition coil. I have it configured that when I turn the key off it grounds the coil to shut it down.
Correct there is no spark after I turn it off the first time and then try to restart it.

Good. Where did you get the ignition coil, is it genuine Kawasaki or off brand? What is the air gap set to?

 

[txmowman]

Good. Where did you get the ignition coil, is it genuine Kawasaki or off brand? What is the air gap set to?

If a genuine Kawasaki part, what is the part number of the coil?

 

[KyleM81]

If a genuine Kawasaki part, what is the part number of the coil?

Yes we got it from the John Deere dealer. AM121810. I used a business card to set the gap

 

[txmowman]

I believe that is the correct John Deere part number for the JS00 spec. I don't have a JD cross reference. Have you tried disconnecting the ground wire to the coil and seeing if the spark returns?

 

[KyleM81]

I believe that is the correct John Deere part number for the JS00 spec. I don't have a JD cross reference. Have you tried disconnecting the ground wire to the coil and seeing if the spark returns?

Yes I tried that. I was trying to find a wiring schematic for the original ignition switch to see if there were any resistors on that little circuit board in line of the ground wire from the factory that I would need to add, but didnt have much luck. I found a couple but they werent labeled very well. Im wondering if maybe I need to change to a different coil now that everything is hardwired and the circuit board was removed?

 

[txmowman]

I believe that is the correct John Deere part number for the JS00 spec. I don't have a JD cross reference. Have you tried disconnecting the ground wire to the coil and seeing if the spark

 

[txmowman]

No, the coil number would not change. The Kawasaki coil should show 21121-2085 on it. Does it?
If you disconnect the ground wire and there is still no spark then it can only be a failed coil or the magnetism of the magnet on the flywheel is too weak or the air gap is too large. The air gap is .012”, cold. A business card is not the proper way to set air gap. It can work, but business cards come in different thicknesses. If the thickness is within spec, your fine. I think a standard card is .014”. Engine starts fine cold. But when everything warms up and expands, you may be getting more clearance. (A hot engine actually gets hotter for a period once you shut it down) See if you can tighten the air gap, use an actual feeler gauge if possible. Then retest.