Farmall Cub

Posco wrote:Can anyone explain to to me what these electrical wire are coming off the tee on my oil pressure gauge? It has two wires, one leading to a terminal on the alternator and the other leading to the starter switch (cranking motor).

The oil pressure switch is used to excite the alternator.

Oil pressure comes up, closes switch, voltage applied to alternator terminal #1 in the earlier posted diagram. Voltage excites the alternator, starts the alternator charging.

Shut off engine, oil pressure drops, switch opens, disconnects from alternator.

Yep, forget what I said earlier. Pretty clever way to turn the alternator on and off. I'm not sure I ever would have though of that.

You guys are incredibly helpful and i want to thank you. Here is a pick of the Hatachi alternator. There is a wire leading from one side of the pressure switch directly to the starter. Coming off the other side of the pressure switch is a wire that hooked to the alternator. It was spliced at the alternator with two leads attached to the vertical and horizontal spade terminals. The splice was soldered and one of the spade adapters is missing but it plugged to the spade directly above the one pictured. What becomes of the post marked "Batt" on the alternator? I don't have notes that anything was run to/from it.

I have run a wire from the distributor to the ignition switch.

Is there any simple way...for my benefit...to recap what we've been over?

Posco wrote:What becomes of the post marked "Batt" on the alternator? I don't have notes that anything was run to/from it.

Refer back to the wiring diagram on the first page of this topic. The alternator Bat terminal should be wired as shown.

Something wrong with the alternator. The black wire coming out of the hole in back right side of the alternator shouldn't be there. Unless it's the battery terminal wire. At this point I don't know. But the individual who installed the oil pressure switch knew what he was doing.

My current thought is that I would replace the Hitachi alternator, in unknown condition, with a single wire alternator. I would do that rather than trying to straighten out the current wiring system and then find out that the Hitachi didn't work.

With your guys help I think we may have conquered it. I got all of the wiring put in place with the exception of the light switch...it started raining and I'm working outside. Of course, the hood and gas tank are removed so it would crank but not run with the gasoline deficit. I couldn't check the ammeter to see if it was charging but nothing was smoking. I consider that a victory.

If I see the battery is not charging I'll go the with the new alternator as suggested.

Thanks for all of the help.

Here's a terrible pic of my new alternator. You can see the spade terminals slightly to the upper left. A little right of 12 o'clock you can see what I gather is a small condensor with a wire leading from it to a post. There is a loose nut on that post so I gather they intend to pick that up for something.

What wire do I run to that post? It came with no wiring instructions and I don't want to smoke another alternator.