Electrical test/troubleshooting Kohler Magnum 12hp

[handyman 1]

How can I test the voltage output from the engine? There is a purple and white wire after the voltage regulator. Can I just test between them? Is it AC or DC? Should I test both before and after the regulator to isolate if that is the problem. I checked the battery when is was running and it was loosing voltage as it ran.

[TT-(Moderator) 1,160]

It would help if you told us what the engine is and what it's mounted on. :omg:

[handyman 1]

It is on a 312-8. The tractor is a 1990. There are no numbers on the tractor but I got the date from the original sales slip from the previous owner.

[pfrederi 18,551]

You should download the Magnum manual from Kohler as it has complete electical diagnostics.

There is a three wire plug in the regulator. Two White wires on the ends come from the stator. Unhook the plug put your multi meter probes in the white wires, set it for AC and you should get 28-30 volts (if i remember correctly)

If you have AC voltage then hook it back up and check your battery voltage engine off (12.6 is fully charged) and then running should be 13.8 or better...

No AC voltage stator has issues (there are more tests for it in the manual)

AC Voltage but battery voltage doesn't increase when engine is running most likely is voltage regulator is bad...assuming you checked teh wires for opens/shorts