Farmall Cub

Hello Everyone! Well I finally did it. I was a long time reader and fan, but had just never got aroundm to posting anything!! Sorry, don't know why because everyone else says I put in my 2 cents. Well anyway, I am a proud Cub owner and she is a beaut. All has been restored professionally. I am though experiencing one problem that maybe the "CUB GURU's" can help me with, here goes...I replaced the voltage regulator and had no problems with the install. However, the anmeter is bouncing all over, but when I ground the F-term, it looks just fine, and yes I did check all my grounds! Any comments would be helpful. By the way the reason for the name is because when ever I work on any of my Farmalls the Wife always tells me I'm "ALWAYSOILY", but I just can't help getti'n dirty, it's half the fun.

Oily. Sounds like you have a grounding or short problem. Bigdog is usually the expert at these kind of problems.

BTW..... Know your neck of the woods real well.

I think Ron is on the right track. The first thing I would do is verify a good ground on the regulator. You could try running a temporary lead from the regulator mount to the battery ground terminal and see if it helps. If it's not a ground, it's likely a mis-adjusted or defective regulator.

Did you polarize the regulator? You must always polarize any regulator and generator when you unhook them.

Yes, I did check the grounds again and still no change. I did also follow Rudi's flow chart to the electrical regulator flow chart. Thanks for the suggestions. I guess the only two questions I have is that can I keep the ground wire from the battery post connected to the regulator base, as BIG DOG suggested and is it so bad to keep the F-term of the regulator grounded to the regulator base. It does seem to charge the battery alot better, not only on the anmeter but also on the voltage meter. I just hate to scrap any more oaf that new paint job I got. Thanks again!

As for as grounding the regulater itself, a wire under the head of any mounting screw to a bolt that will provide a ground will do.

Keeping the F terminal grounded all the time will lock it on full charge. The only way that will create a problem is if you put long hours on your cub, then it will overcharge the battery. If you use it like most people now use a cub (5 or 6 hours a week) it won't hurt anything

John *.?-!.* cub owner wrote:If you use it like most people now use a cub (5 or 6 hours a week) it won't hurt anything

Well maybe. I looked back through this thread and couldn't find any place where Alwaysoily said which version of a charging system he has. If it is the early cut-out system, leaving the F grounded is fine. If it is any of the later generators that had a voltage regulator, the output capability of the generators is enough higher that it would not be a good idea.

The charging system is still the original 6 volt possitive ground. The generator was recently rebuilt and charges great. As far as the voltage regulator, it is brand new from NAPA, so I believe that it does have the cutout rely(maybe?). By the way thanks for all the quick postings. I might even get to cut my knee high field tonight, that is if the rain doesn't start AGAIN!

I also forgot to mention that the Cub I own is a 1950, and all is original, right down to the rebuilt generator. Thanks again.

There were at least 5 different 6 volt, positive ground generators installed on the Cub at the factory, more replacement versions. The only one I think can be savely used with the F permanently grounded is generator 45634D (Delco 1101355 on the tag) which was used from '47 through the middle of '50. This was used with cut out relay 46412D (Delco 1116766). Any other generator is higher output than this one and could easily cook the battery.

The box shaped things we collectively call regulators all contain a cut out. Many of them also contain a voltage regulator. The voltage regulator is what prevents overcharging. Grounding the F bypasses this function.

The change to a system with a voltage regulator happened at serial 115403.

Thanks Jim for the indeepth info. You really schooled me. However after doing everything that was suggested to me I still can't figure out the bouncing ammeter. I do want to wire my Cub the correct way and not use the F-term ground. I am charging the battery now with a possitive charge on the ammeter at half to full throtle(extreme bouncing), but I do show at the battery and regulator voltage with a volt meter at about 6.10 to 6.40v. Is that the correct voltage that I should be seeing? The only thing left to replace is the ammeter, but seeing that it doesn't bounce when the F-term is grounded, maybe it still is good? Still original hate to get rid of it. Not to sound like a broken record, but I did check all the grounds again this time with a ohms meter and all had continuity. Thanks for all your advice and help.

oily, Jim is right about not leaving the field grounded on later model generators, Both mine are the old style and I tend to forget about the higher output generators used on the later ones. If your "regulator is mounted on top of the generator it is actually a cutout, not a regulator. if it's elsewhere, it's an actual regulator. The voltages you gave are a little low for a battery while the generator is charging. 6 1/2 to 7 1/4 is normal for the engine running and the battery charged. If you are using a digital meter to read the voltage, many of them will lie to you due to the inherent electrical noise on a generator charging system.

I am leaning more towards the regulator being the problem. Is the voltage you gave with the regulator connected or with the F grounded? What are the voltage readings each way?

How wildly is the ammeter bouncing? From what reading to what reading and how rapidly?

Here is a cutout with the cover removed

Here are my two readings. With the f-term grounded and running at 3/4 throtle I read between 6.5 and and 7.0v. Without the F-term gounded I have readings between 6.0 to 6.3v. Also with the F-term grounded the ammeter is showing about 22amps running at full throtle and without it smacks both sides of the ammeter so fast that it looks like a blur, but when I back the throtle down to about 3/4, it settles down to about only 8amps.(amp readings are per the cub ammeter, the voltage readings are with both analog and digital meters). Thanks