Cub Electrical

Michael Shouse · Sep 28, 2011

I have a Farmall Cub that I am having an issue. Undoubtedly, I have hooked the battery up backwards. It is the original 6 volt with a positive ground. I think I hooked the battery up backwards and now it will now run for very long at a time. It shows it is charging but I have to jump it off every time I start it. This is the tractor my wife uses when we mow so I need to get it fixed. Any ideas???

Bob M · Sep 28, 2011

Michael – If the battery is installed negative post grounded, the ammeter will read “backward”. IE when the ammeter shows charge, the battery is actually DISCHARGING.

However as you have found, the engine will run a long time (many hours) from a non-charging battery before it goes flat. (If your Cub has a magneto it will run indefinitely – the battery is used only to crank the engine).

Solution:
1 – Charge the battery
2 – Reconnect the battery with the positive post grounded.
3 – Check ammeter operation: With the engine off, turn on the ignition or lights. If the ammeter shows discharge you are set. However if it shows charge, swap the wires at the two ammeter posts.
4 – Polarize the generator: Again with the engine off, momentarily jumper the BAT and GEN connections at the voltage regulator or cutout relay.
5 – Now start the engine and see if the ammeter shows charge when running at half throttle or faster.

If it now charges you are all set. If it does not, post back what you find and we’ll help you identify the problem.

Cub Electrical

Michael Shouse

New User

Bob M

Well-known Member

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