electrical issue on Farmall Cub 1951

B Rankin

New User
My Farmall cub has a short. I have replaced the starter the coil and the battery. When I pull the starter lever I can see it spark at the plunger. I also replaced the 12volt from 6 volt restrictrer (not sure what it's called but it was smoking)all to no avail. When all is hooked up and I try to start. There is dead silence not even a click. Any ideas will be appreciated. I know this is tough one because it could be just about anything. But I am at wits end. I don't see any frayed wires. What could it be? P.S the fuse is good and does not blow. Of course I unplug everything so not to short anything else after each start attemp.
 
check the small wire thats on the starter it goes to the amp gauge and switch if there not on certain way they will ground out I had one do this to me a couple of weeks ago
 
Spark at that starter switch could well be a bad switch. The battery cable on that is insulated so if that insulation is going bad you could well get a spark at that as you call plunger
 
The starter switch is designed to us a copper stud, which is under the switch and part of the starter. This stud wears as it is used to carry hundreds of amps. As it wears the switch also wears. When worn to the limit, the switch will be intermittent, then just spark, then not work. Some new switches are made with the mount holes too far away from the stud, causing even new switches to fail to operate.
Test. Put the tractor in neutral. Lock the brakes and or block the rear wheels. Assure there is no open gasoline or leaks. Remove the negative battery cable from the starter switch and make sure it touches nothing. (a chunk of hose on it can be your friend) Remove the switch from the starter. Hold the big cable alone. remove the "hose", and firmly touch the cable end to the starter stud. It will spark radically but one of two things will happen. The engine will spin briefly (as you react and jerk the connection off of the stud), or it will continue to do nothing. If it spins the switch can be modified to widen the mount holes to allow it to reach the stud (about an eight of an inch ovaling of the holes).
If it doesn"t spin loosen the starter from the engine (rubber hose on the cable end again) and wiggle it If you hear a spring like snap as the starter is loosened, you found the problem. The starter drive pinion needs to be replaced with a new and improved style with no big spring).
If it made no sound and after tightening it still sparks with no starting, the starter is internally shorted. Repair or replace. Jim
 
I agree with JimN.....problem's most likely a worn out starter switch. (Sparking from the switch assembly is a sure sign.)

The switch is cheap and easy to replace - I'd start there.
 
J Nicloleson, After reading your reply you seem to have the best idea. All replys are greatly appreciated! But J. I can start the tractor if I bypass with jumper cables and do a direct application. I use a screw driver and push in the switch and it starts right up. All is well until I need to restart. But can the switch be bad if I can still start by pushing down on the switch during direct current? My ignition switch works fine when I turn the tractor off.
 
If you are jumping to the connection stud on the starter switch with a jump from an external battery, you are effectively eliminating the installed battery and the connections from it to the starter.
Steps:
Remove the nut and washers from the switch that hold the battery cable, and the wire to the amp meter. Clean this connection with 120 grit sand paper and reinstall. Try it.

Remove the battery terminals at the battery and clean them, then replace and tighten. Try it.

Check the voltage of the battery. If 6v it should be 6.3 volts or more.

If 12v it should be 12.6v

If less than that (either) it needs to be charged and retested. If still low the battery is probably bad.

Charging voltage is 7 volts to 7.2 volts on 6 volt systems. It is 14.2 to 14.6 volts on 12v systems. Start a new post, this one is getting old and far back in the pages. (I use the classic view) Jim
 
To reply to your last. I am using the battery on the tractor not an external battery. That is why I am puzzled. It starts fine with jumper cables. But it won't without. I hook jumper cables to the existing battery and to the start post and a ground on the tractor and push the starter switch with a screw driver and it starts like it was supposed to. I cleaned both terminals. Do I need to replace the ground cable also? I'm just out of ideas.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top