Cub Ignition failure

mountain4don · Aug 17, 2015

I went out to mow grass with our 1959 International Cub LO-BOY with battery ignition last night and it wouldn't start. The engine cranks just fine. This morning I hooked up a timing light to #1 spark plug and no spark. So then I hooked up the timing light to the spark coil top connection that goes to the center of the distributor and no spark there either. So I am now replacing the points, condenser, rotor, and distributor cap to see if that helps. But when I took them out of the distributor they didn't look too badly burned and the gap still looked to be about 0.020". So, what else could be the failure? Coil maybe? How can I test the coil? Or what else could be wrong?

souNdguy · Aug 17, 2015

more testing.. less spending.

might have been as simple as no power to the coil. IE. bad ignition switch! or just DIRTY points..

John T · Aug 17, 2015

If you work step by step through my Ignition Troubleshooting Procedure you may be able to find the cause of no spark, with no fancy tools or equipment or meters generally required, maybe a jumper wire or a test lamp. So often its just the points are burned or pitted or carboned which a good cleaning or light filing may cure. If only gray oxide coated running a dollar bill through them may brighten them enough, check the gap also.

John T
John Ts Ignition Troubleshooting

Charlie M · Aug 17, 2015

Is it 12 volts with a resistor to get down to 6 volts at the coil.If so chances are good the resistor is bad.

old · Aug 17, 2015

ALWAYS ALWAYS trouble shoot then part never part then trouble shoot.
That said you need to learn how to test the point to see if there working as they should. You cannot see with your eyes if there good.
Turn the ignition on with the cap and rotor off so you can se the points. They will most likely be sitting closed since they are close more then they are open. Take a screw driver and lay it across he point and if you see a spark the points need to be cleaned. Point corrode fast and they need to be cleaned once in a while

mountain4don · Aug 17, 2015

It is the original 6 volt, positive ground electrical system.

David G · Aug 17, 2015

I totally agree with Old, troubleshoot and ONLY replace ONE thing at a time.

John T · Aug 17, 2015

Good info, my Troubleshooting Procedure covers that well. As I mentioned its often the points that are the problem. Good luck let us know what you find.

John T
Easy way to find the problem

mountain4don · Aug 18, 2015

Thanks everybody for your help. I already had a new set of ignition parts hanging on the wall in the shop since I have three of these tractors that take the same ones. And rather then spend a lot of time trying to make an old set of points work, or exploring a bad condenser, I just replaced all of the parts. Its been awhile since I had tuned up this tractor, and it is used daily for production grass cutting and fence work on the farm. So I didn't have much time right now to get it running and back working. I copied and used some of the procedures you guys presented to make sure everything was operating properly before firing it up. And it runs again! Just a few weeks ago I had dismantled the rear end of the tractor and replaced the brake bands and seals, having it out of commission for that for a week. And a lot of the grass still hasn't been cut and its a foot high! Thanks everybody for your help!

Cub Ignition failure

mountain4don

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souNdguy

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John T

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Charlie M

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old

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mountain4don

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David G

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John T

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mountain4don

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