Voltage Problems
 

I'm at wits end. The tractor is a 1250 with a K301. Replaced the amp meter with a volt meter when I restored the tractor a number of years ago. Always read 13.7 to 14 volts, but yesterday noticed the voltage drop to 12 volts then would jump to 14 volts. Did all the checking of the stator, 31 to 34 volts AC on the leads coming from the stator, did the resistance check .3 ohms across both leads and resistance one lead to ground. All testing proves the stator is working properly. Soon as I hook up the rectifier/regulator (which is properly grounded) can't get more than 3 to 4 volts. I had a new regulator, tried that same results. Any suggestion on what to try next would be appreciated.

You either have (A) a bad V/R, or (B) a bad ground, and (C) maybe both.

:beerchug:

Given that you've swapped the regulator with no change, Rolands suggestion about grounds is a good one.... plus it's cheap and fast.

Easy check is to run a wire from the regulator body (ground) directly to the negative terminal of the battery temporarily and see if the voltage reading stabilizes . If so, then you know you've got some cleaning and tightening to do.

Any results?

Well I did all the checking as mentioned above, but found it was (D) Key switch. After starting up the tractor and running at full throttle the gauge read 14v, turned the lights on dropped a little, turned the PTO on dropped to 12v. For some reason I rocked the key switch back and forth and the voltage would jump from 12v to 14v. Changed out the key switch, problem solved.

Did you look real good at the PLUG that attaches to the switch?
Corrosion occurs on the female connectors in the plug, especially the one that goes to the battery.
A lot of times the plastic plug is melted somewhat because of arcing, then heat build up occurs because of poor conductivity.
That leads to removal of the thin anti rust plating, that leads to rust/corosion and,---- well you see the down hill spiral.
If the plug shows any corrosion in the female terminals, replace them on the wire ends.
They are available without replacing the whole harness.
Also they are available as a pigtail with plug.
then one just has to solder/shrink tube the pigtail to existing wire harness.:beerchug:

Great info here. Thanks for sharing!

Glad to see another "solderer" rather than "crimper".

Each has their place, I suppose but solder is forever :-)