Cub Cadet 71 Battery

SPT

Member
I have my dads old c Cadet that he purchased new, using it regularly. All of a sudden it runs down batteries while using it. Charge battery and let it sit it will start fine, run it a couple of hours and battery will be dead, Any thoughts?
 
Presuming it has a starter/generator and not a stater with a solid state rectifier. Sounds like the starter/generator is not functioning, as the generator function should charge while running. Before starting take a voltage reading at the battery and then compare that to a reading while the engine is running. If it is lower while running check the voltage on the A terminal of the generator, should be around 13.3 . If that is low the generator needs a rebuild, if okay check the voltage on the B terminal of the voltage regulator, if it is low then the voltage regulator should be replaced. That's if the wiring is all intact with no open/broken wires exist.
 
I second checking the starter generator system. The battery on my old Yazoo finally bit the dust. I figured it was just old age. I found 2 broken wires on the voltage regulator. I fixed them the other day and put the battery in today. Once I get the ignition system in, I will be sure to check if it is charging. I might even put a ammeter in it if I have a used one around here.
 
SPT:

Your tractor has the Delco Starter/Generator (S/G) charging system.

Take a meter and measure across the Battery Terminals when the engine is running at 3600 RPM's or WOT. A proper voltage would be around 14.5VDC.

Here is a troubleshooting guide that will quickly narrow it down.

TROUBLESHOOTING a No Charge:

1.) Confirm that the battery wire to the BAT terminal of the Voltage Regulator (V/R) has 12VDC to ground. This terminal is always powered even if the key is off.

2.) Remove the Blue & Yellow wires from both the Starter/Generator (S/G) and the V/R. Check the wires for GOOD continuity (zero ohms). If OK, re-attach at both wires at both ends.

3.) Start the engine and run it at full throttle. Using a jumper wire, temporarily ground the F terminal of the S/G to the battery and/or chassis ground. The S/G should charge at this point, and you should hear a definite drop in RPM’s If you have a Amperage Gauge, you should notice the indicator needle in the charge position. 15 Amps would be the Maximum Charge Output from the Delco-Remy S/G. This means the unit is charging, but it is an unregulated charge. Never leave your Cub wired up this way!

a.) If the unit DOES NOT charge when the F terminal is grounded (no reduction in RPM’s is noticed), the S/G is defective.

b.) If the unit DOES charge (the RPM’s drop), then the V/R is defective.
 

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