Yanmar Alternator Problem

QBH · Dec 14, 2015

I have had a problem with the alt and battery on my YM2210D for a while now. Last week, I replaced the alternator and battery. I measured the battery voltage with the engine off, and it is about 12.4. With the engine running, even at high RPMS, the voltage is only about 12.8. It seems like it should be higher, shouldn't it?

BTW, the belt is good and tight.

Any thoughts or suggestions?

Thanks,

Larry

devildog1 · Dec 14, 2015

Voltage is on the low sides for both on engine off and running. The battery should read in the range of 12.75 to 12.90 when fully charged. When engine running and tested on battery or alternator it should read somewhere in the 13.25 volts or higher. Check your grounds on tractor frame and battery and scrap clean for a re-check on voltage.
DevilDog

QBH · Dec 14, 2015

Good thought on the ground. I will check that. I am checking the battery voltage right on the (brand new) battery posts, so I know that is right, but I dont know that it is getting a good ground. Thanks.