Farmall Cub

Good afternoon. This problem must be explained somewhere but I can't find it. I have a 1953 farmall cub with a 6 volt positive ground generator and voltage regulator. It has been charging ok until last week. I have the cover off the regulator and when starting the tractor, the relay points jump for a couple seconds then when they close, the ammeter pegs out on discharge. I am afraid to run John's test as I don't want to mess anything up. Does anyone have any idea what's going on? Thanks, Bill

Let's start with the simple things first. Repolarize your generator. Here is how it is done.

http://farmallcub.com/phpBB2/viewtopic.php?f=11&t=56748

I polorized it twice, still the same. Would a bad voltage regulater do this?

There are lots to things that could be causing the problem. What I try to do is first ask myself if anything was done to the tractor since it was working correctly. Sometimes changes to wiring, battery hookup, etc., may point to the problem. If nothing is apparent, then wear and tear may be the cause. The next thing I would do is, with the ignition turned off, pull a strip of coarse paper a few times between each point as you manually hold the points down lightly against the paper. A piece of paper from a shopping bag will work. Sometimes the point surfaces can build up debris on the surface that prevents solid contact.

I filed the points and blew them off. I took the wires off the generator and show a continuity between the A and F posts. I wouldn't think there should be, shorted on the inside? I was mowing when it went haywire.

If the the tractor starts OK, we can assume your battery cables are not corroded. When facing the regulator, the cutout relay will be on the left side. This cutout has to close before you will see a positive charge on your ammeter. If the cutout relay does not close after the tractor starts, have someone lightly hold the contacts together while someone observes the ammeter. If you get a positive charge on the ammeter, your generator is good. If the points remain closed after you manually close them, the points are either slightly too far apart or your generator is not putting out enoungh current to energize the magnet in the relay to initiate the closing of the cutout points.

try this

I'm afraid to try the trouble-shooting chart, as soon as the relay points close, the ammeter needle pegs to discharge. I don't want to burn something out . when facing the voltage regulater on the right side of the tractor, my relay points are on the right side of the regulater. I have the 2 point reg., 3 fixed brush gen. Thanks, Bill

We need to make sure we are both referring to the cutout relay. The cutout relay is connected to BAT terminal on the regulator. Here is an an instruction sheet from Delco Remy. It describes both the two and three relay regulators.
A negative reading on the ammeter means current is flowing from your battery to the regulator and/ or generator. If the ammeter needle is pegged to minus, it suggests a short in one of the two units. When you turn the ignition on without the tractor running, what is the reading on the ammeter?

http://www.ruiter.ca/mc/info/PDFs/1R-116.pdf

The needle is just left of center about 1 mark.

The ammeter will normally indicate a slight discharge when you turn on the ignition with the tractor not running. This discharge is through the ignition points and is a normal occurance. It appears there is nothing unusual until the tractor starts and the regulator points close. It appears to me that your regulator is defective. I say this because the relay points in the regulator would not close unless your generator is putting out current. This seems to discount the generator as the culprit. I am not sure why you are getting what appears to be a dead short when the regulator points close unless there is a short in the regulator. Instead of the a normal situation where the current from the generator would be directed to your battery with a positive indication on the ammeter, you have the reverse occurring occuring - battery to regulator - as soon as the points close.

Thanks. I will get a new regulator and try it. I ran the motor test on the generator, neg. to A. pos. to a gen ground, F to ground. The gen ran, when I took the F ground off, it quit. I read where the gen should have sped up. Is this always the case? Thanks for all the help. My cub is all original, I use it to plow snow in the winter and mow the woods in the summer. Bill

From what you describe, it seems to confirm that the generator is working. I would go with a new regulator. Review the comments on regulators in this forum. Members have had different degrees of success with some of the cheaper foreign units. Compare and price before you buy. Perhaps those who have bought regulators may wish to comment.

This may be a stupid question, but are you sure the battery has not been removed and reinstalled backwards? It is the only thing that really makes since at this point. Buy or borrow a voltmeter and check the voltage, paying attention to polarity. I have seen a generator polarized wrong and charge the battery backward, but it is rare.

The battery is pos ground, neg hot. I have the wires off the gen., shouldn' I get a reading with the tractor running off the A post on the gen? I will be in and out do to honey-dos. Thanks, Bill