Farmall ampmeter

Is the amp meter supposed to read backwards on a positive ground system? j

No. You need to reverse the leads on the ampmeter.

If she was originally Pos ground (like 6 volt systems) and the battery polarity hasnt been reversed SHE SHOULD REGISTER CORRECTLY AS IS. A common problem is when the battery polarity gets reversed but the ammeter leads didnt get swapped as Rusty mentioned THEN THEY DO REGISTER BASS ACKWARDS. If the ammeter is wired right if you turn lights on not running it should swing over to - discharge of course. If you start messing with battery polarity Id Polarize the genny prior to start up.....

John T

I'll ad to Rusty and john's Info:
If the battery appears to be Positive ground, ie, the positive terminal is actually connected to ground, then I would check the actual polarity of the battery. Use a good volt meter with the leads in the correct holes, and make sure positive is positive. Batteries can be charged backwards if they are really dead.
If it is, and it is working OK charged backwards, I would remark the battery so it is really clear it is wrong, but OK. Then I would either turn the battery around and repolarize the gen to make it POS ground (amp meter reads correctly)
or I would leave it alone and use it until it needs a new battery (assumes no others would be messing with it. JimN

Yes the positive does go to the ground strap, and Im not sure what the polarity of the battery is. It is a 6 volt system still. On thing I have always had trouble with is the battery will go dead after so many starts. I take the battery out charge and its good for awhile?. I havent really looked into it much, just dont have the time, and I have other tractors to use. But its been this way since I got it 4 years ago. The light switch also has High lights, low lights, off and something you turn on for the generator if I remember right, I have to look it up. I dont really understand what that does. Maybe turning it on makes the battery charge? J

The following assumes that the system has a cutout relay, not a true VR.
Light switch is HLDB which means:
Full CCW is low charge (field is grounded through a resistor on the back of the switch to ground through the switch body)
Next CW position is High charge, field is grounded through light sw body Max charge (used for 1/2 hour after start at more than 1/2 throttle)
Next is Dim lights, (Full charge rate, and lights are powered through a resistor 9also on the back of the light sw))
Next Full CW is Bright lights and full charge rate. No resistors in the field ground, and none in the lamp supply.
If you have been charging it with the polarity of the charger the same as the bat terminals, it is OK.
Not running, set sw to second from full CCW. Jump between the Gen and Bat terminals on the Cutout relay with a copper wire for one second (will spark).
Start it and run it at 3/4 throttle. Look at the amp gauge. if charging Cool beans.
set charge at L and see if it reduces the charge.
If no charge, ground the F terminal of the generator (while at 3/4 throttle) if charge, it is the wires to the sw. If no charge, see the following link!!
John T charging reality

I don't think he is charging the battery. What he is seeing is the current draw. Drom his description, the battery goes dead. SO I believe your ammeter is telling the truth, and you have a generator or wiring fault.
Put a voltmeter on the two battery posts when running at 3/4 throttle. You should see about 7.5 volts.



Gordo

Good thought, too, Gordo about the discharge. If he's running on a magneto with the lights off, he wouldn't show any draw after starting. So all I'd add, if he does have a magneto is to check which way the needle moves when he turns the lights on, with the tractor off.

As for the possibility of a short draing things smoeplace, I'd also suggest noting the position of the needle with the battery disconnected and, after making sure everything (lights and ignition (if it is a factor) are off, and see if the needle changes position with the battery connected. If not, and no spark as the battery is hooked back up, then I'd start with turning on the ignition switch (if it has a battery ignition) to see how far the needle deflects then. A little would be consistent if the points are closed, but it would show more if any short were along the primary feed to the coil. Just something in addition to the not-charging possibilities.

I will check tomarrow what the amp meter does with the tractor off. Its in a machine barn now for the winter, but maybe I"ll look at it tomarrrow. I havent run it since September, so I dont know if it will start. Gonna be cold again tomarrow.Thanks, jay