Farmall Cub

This morning I finished wiring my '50 model. I hooked the battery up and
and was able to whirl the engine over. Next, I pulled out on the cut-off switch and got good spark at the breaker points. I don't have the fan belts on or tank, carb, etc. I wanted to make sure the wiring was good before I went any futher. Question is, shouldn't I see a discharge on the ammeter when I pull the start lever? I'm not seeing it, so I think I have a broke ammeter.

im not sure what is wrong, but i did notice that your location is my last name. my name is Aaron Monroe. where is Monroe at?

btw good luck with the cub, and yes, its probably the ammeter. also id recommend double checking your wiring.

Check your grounds...that ammeter grounds to the dash, which grounds to the chassis/torque tube. Your problem may be paint.

Ask me how I know.

Not clear you have a problem. Does the tractor have a magneto or battery ignition?

The starter is not wired through the ammeter. If it was, cranking amperage would blow it. If you have a magneto, it uses no battery power so switch on and cranking won't show anything on the ammeter. If you have battery ignition, turning the switch on will show a discharge only if the points happen to be closed (usually are when stopped). While cranking, you will usually see movement of the ammeter needle.

If the ammeter doesn't move when the battery ignition switch is turned on with the points closed, something is wrong. It may be a bad ammeter or a wiring problem. Where is the feed to the ignition switch coming from? If it is connected to the starter side of the ammeter, the ammeter won't see it.

Starter lead does not go through the ampmeter. It would have to be able to read over 100 amps if it did. Amp meter doesn't need a ground, though light switch (for charge control) and kill switch (for a mag.) both do. If you have a battery ignition you should see a slight discahrge when the switch is turned on if the points are closed, but not if it's a mag.

After a tedious leaky toilet repair I was able to go re-trace the wiring. All correct as per the diagram on the FAQ page. It is the battery ignition. The only switch is the on-off push pull on the dash. The dash was painted with a couple of coats prior to installing the ammeter. Is there anything I can check with a volt meter? I was encouraged by seeing spark at the points, but...............?

After futher review, I found that I didn't tighten the + side lead on the ammeter. Been one of them days.
It now functions the way Jim Becker said it should. When switch is pulled out, about a 2 or 3 amp drop. Pull the start lever and the ammeter needle twitches to the - side with what appears to be each point contact.
With the switch in and the starter engaged.......nada. So far, I think it's correct.

Actually, it pulses toward the + side.

hr's49cub wrote:Actually, it pulses toward the + side.

Harold,

I would say that means either the ammeter or the battery is connected backward.

That's why I wish I had an original ammeter. It has a SW (Stewart-Warner?) +20/-20. The scale isn't as good as the original. When I pull the switch to the run position, the ammeter goes from 0, to about -3. I'm assuming the points are closed. When I engage the starter and the engine rotates, the needle pulses back to about zero. I do not have the carb on it, so I haven't started it. Maybe tomorrow. I wasn't clear with my edit. I have yet to see anything to the "+" side.

You won't see anything to the + side until it is running and the generator charging. To test it though you can hook a battery charger to the generator lead. Remember, battery and charger should both have + leads going to ground.

" Amp meter doesn't need a ground, though light switch (for charge control) and kill switch (for a mag.) both do.

OOPS I jumped ahead of my brain. Sorry.

Where's Donny???? Grounds are bad for ammeters Need some of that dielectric stuff so they'll work right.

John, could you explain how to hook up battery charger to test ammeter? I'm having the same problem. Needle not moving. Lonniebug57

Hook + lead to ground and - lead to wire going from ammeter to regulator/cutout. If charger shows charge, the ammeter should show the same. If charger works, but no reading on ampmeter, then meter is probably bad or wired wrong. Before assuming the ampmeter is bad, disconnect wire between battery and regulator/cutout to make sure it hasn't stuck and current is flowing that way, and take readings again.

If no charge, check ground on charger lead first. If ok, then move - lead of charger to other side of ammeter. If starts charging them ampmeter is open internally.