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Cub tractor won't spark

J

johnald

Member
Here is the run down:
cub has been sitting for a year while I found time to work on it.
rebuilt motor, a little paint and finally got it back together. Wouldn't start when I first cranked it so I started checking the usual suspects. Whittled it down to not getting spark so I checked the coil, it seemed out of speck so I replaced it. When I did this I went from an old 12v coil to a new 6v coil with external resistor as that was all I could find at the time. Points looked good but I replaced them anyway to be sure. After replacing points, condenser and coil I pulled a plug to check for spark. As I cranked the engine I got one beautiful spark then nothing. I went to get a tool or something and accidentally left the key on. The resistor got pretty warm which did not seem right. Makes me think there is a short somewhere but I can't find one. Every connection and wire seems to get the proper voltage but I haven't been able to reproduce a spark. I'm pretty stumped on this one and I need to move on from this project and get this tractor running. Any help/advice is greatly appreciated.
 
I had a Cub once that wouldn't start and it liked to drove a friend and I crazy until we discovered that it had a gear driven rotor and some of the gear teeth had stripped out and the rotor did not turn, check rotor
 
The reason for the resistor and/or coil to get hot is because your short is the points. Points open and close to produce spark. Since your coil is basically a transformer, and transformers need ALTERNATING CURRENT to work, the points provide the equivalent by producing pulsing DC. If the engine is stopped with the points closed and the ignition on, the coil, resistor, and points will get warm.
I suggest that you check to see that your distributor (or Mag) is actually turning when you crank the engine.
 
With the points closed and key on the resister will in fact get hot and that is normal. I'll almost bet if you put the old condenser back in and clean up the points you will have spark. Reason I say to clean the point is leaving the key on may have burned them a bit
 
Did you remove the distributor from the engine? You may have fried the resistor when the switch was left on. If you're using a 12 volt battery you should use NAPA's coil P/N 1C14. No ballast resistor required. The - minus terminal wire on the coil goes to your points. Hal
 
My Dad had a cub when I was at home.
It got hard to start, would run the battery down and then crank it till blue in the face. Sometimes it would start and other times not.
It was several years till one day I checked the pass thru insulator to the distributor and it was cracked. Wrapped a piece of of inter-tube around the wire and pushed it into the distributor housing and several years of frustration was over.
I'm 72 years old now but will never forget how much time we spent getting that thing started. WaltM0
 
ended up being the ignition switch. It tested good for continuity and voltage but just wasn't letting enough current through. Started right up after I replaced the switch, ran for a while then lost oil pressure and power. Parked it and am deciding how to proceed. I am very frustrated but I really appreciate everyone's help.
 
You said it lost oil pressure and power. did it quit like you had turned off switch? I worked on a friends last summer that the camshaft gear (press fit) had come off the camshaft. No oil pressure (oil pump is on rear end of cam shaft), and engine coasted to a stop as if it had been turned off.
 
no, I shut it down. It was losing power and blowing smoke out of the dipstick and oil pressure was at zero.
 
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