1966 JD 110 Electrical Help Please

irwin · May 26, 2009

Wombat125 said:
A little update...

Per several of your suggestions, I put a meter on the battery to see what the charging system is doing. So here it is.

At slowest idle, the generator is putting out just barely over 12 volts. Then as I increase engine RPM, the charging voltage increases comensurately up to about 13.6 volts at about 80% throttle. Increase the throttle past 80% and the charging voltage abruptly drops back down to just over 12 volts. Once this voltage drop occurs it sticks there, regardless of what I do with the throttle thereafter.

So now what do y'all think?

Thanks!!

Mmmm, That doesn't sound right. I'd say you have a charging system problem..it' doesn't appear to be severe, yet.... but it's not right.

mfreund · May 26, 2009

Sounds like a bad requlator to me.

t man · May 27, 2009

My guess is the brushes in the generator are worn.To trouble shoot that you need to start it up and increase the throttle until you hit the point where your voltage drops back to 12.With your volt meter connected to the battery,tap the generator with a hammer handle or screwdriver handle lightly.Tap the end where the brushes are located,(the same end that the wires come out).As you are tapping it watch your volt meter if your voltage comes up to 13-14 volts or fluctuates as you are tapping your brushes are worn down and need to be replaced. Tim.

albatross · Jun 9, 2009

I have a 66 110 as well and it didn't seem to be charging. I rewired, and now it seems to be charging. As far as the GEN. light mine seems to be on when it's charging and dims or shuts off when it's not. That sounds opposite of how Wombat125 says it should work does anyone know for sure?

Not knowing for sure how this thing works I am going from what I see visually and what seems to make sense. I opened up the voltage regulator and there are to relays in there. When the tractor is off both are closed. When it starts one opens. When tested with a volt meter at the battery I am getting 12.5v not running and 13.25v when it's running. I assume that means it's charging. The GEN light is on, now when I manually open the relay that stays closed the voltage at the battery drops to 12.5v and the GEN light dims or goes out. That all seems like it makes sense and is working correct. What do you guys think.

Thanks TD

Wombat125 · Jul 3, 2010

Well, it only took 14 months, but I finally got her fixed.

As it turns out, t man Tim was right. I replaced the brushes and she runs like a top. Genny light comes on when the engine isn't running, and then shuts off when it starts.

I even took the opportunity to get rid of the ganky pipe exhaust extension the previous owner installed.

Now I can put her back to work doing some trim mowing around the house and trees.

Thanks for all the suggestions. I am always impressed by the quality of knowledge in this place.