More questions on 39 M

Anonymous-0 · Dec 2, 2010

As I understand it the 39 M is supposed to have a cut out relay instead of a regulator. How do I tell the difference between the two? After looking again I might have a cut out relay. Where should the cut out relay be mounted on the 39 M? Is there any way to check and see if it is any good?

I also need to check over the magneto on this tractor. I assume that this would be the H4 magneto? How do I make sure I don't get knocked on my tail while working on this thing? I have heard of guys getting nailed by them. I have never worked on a mag. Serviced many a distributor. Is it more or less the same kind of deal working on a mag?

One other thing. The repsonse from the governor seems to be very erratic. It seems like you have to move the throttle lever quite a ways before you get any repsonse and when you do you get a response it is sometimes more than you wanted. Same with throttling it down. Took the cover off of the governor and everything in there appears to be well lubed and the spring is not broken. Any suggestions?

Bob M · Dec 2, 2010

A cutout generally has only 2 wiring terminals. A VR will have 4 terminals.

Also a cutout is usually a small, rectangular "can". OTOH a VR enclosure will be about 3" square.

Cutouts are almost always mounted atop the generator. If the original cutout was replaced with VR, the VR might also be mounted atop the generator. But it could also be mounted almost anywhere else between the generator and the ammeter box depending on the whim of the owner.

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The throttle response problem sounds like a sticky or misaligned governor to carb linkage tube.

First loosen (but don't remove) the 2 screws that clamp both end of the gov to carb tube. Now with the governor handle set all the way forward (idle), wiggle both ends of the tube up and down. Then retighten the clamp screws.

If that doesn't fix it, you'll need to remove the carb and gov to carb linkage and check for sticking/binding parts.

rustyfarmall · Dec 2, 2010

(quoted from post at 07:08:42 12/02/10) A cutout generally has only 2 wiring terminals. A VR will have 4 terminals.

Also a cutout is usually a small, rectangular "can". OTOH a VR enclosure will be about 3" square.

Cutouts are almost always mounted atop the generator. If the original cutout was replaced with VR, the VR might also be mounted atop the generator. But it could also be mounted almost anywhere else between the generator and the ammeter box depending on the whim of the owner.

----

The throttle response problem sounds like a sticky or misaligned governor to carb linkage tube.

First loosen (but don't remove) the 2 screws that clamp both end of the gov to carb tube. Now with the governor handle set all the way forward (idle), wiggle both ends of the tube up and down. Then retighten the clamp screws.

If that doesn't fix it, you'll need to remove the carb and gov to carb linkage and check for sticking/binding parts.

The cut out relay on my 1940 H is the same exact dimensions and has the same appearance as a voltage regulator, however, it does have only 2 terminals as opposed to the 4 that would be on a VR.

Bob M · Dec 2, 2010

(quoted from post at 10:48:40 12/02/10)
The cut out relay on my 1940 H is the same exact dimensions and has the same appearance as a voltage regulator, however, it does have only 2 terminals as opposed to the 4 that would be on a VR.

Good catch Rusty! There are indeed cutouts the size of a VR. But if you pop the cover on one you will find only 1 relay inside (a VR contains 2 relays).

Most CO's however are housed in the smaller rectangular can.

rustyfarmall · Dec 2, 2010

(quoted from post at 07:56:39 12/02/10)

(quoted from post at 10:48:40 12/02/10)
The cut out relay on my 1940 H is the same exact dimensions and has the same appearance as a voltage regulator, however, it does have only 2 terminals as opposed to the 4 that would be on a VR.

Click to expand...

Good catch Rusty! There are indeed cutouts the size of a VR. But if you pop the cover on one you will find only 1 relay inside (a VR contains 2 relays).

Most CO's however are housed in the smaller rectangular can.

Yes, exactly. My 1940 H had been rewired in a really strange fashion when I bought it, but since the CO relay was still there, and also the 4 position switch, I decided that rather than trying to figure out what the previous owner had done, it would be easier to start from scratch and rewire it to original specs. Somehow, in the process, I read the wiring diagram wrong, which resulted in ALL of the smoke escaping from that relay. I was very lucky to find another one, and this time I triple checked the wiring before I cranked up the engine. That was maybe 12 years ago, and it is still working like a champ.

Anonymous-0 · Dec 2, 2010

Okay guys thanks. My CO or VR has 3 terminals. Bat, gen, and F. Do I have a VR or a CO? Is a VR more desirable than a CO? I'll probably try to go with a CO since that is what a 39 is supposed to have.

rustyfarmall · Dec 2, 2010

(quoted from post at 08:09:12 12/02/10) Okay guys thanks. My CO or VR has 3 terminals. Bat, gen, and F. Do I have a VR or a CO? Is a VR more desirable than a CO? I'll probably try to go with a CO since that is what a 39 is supposed to have.

With 3 terminals, I would say it is a voltage regulator. Other than keeping with originality, a voltage regulator IS better. If you want a CO relay that is of the original appearance, you will most likely have to find a used one because I know of no one reproducing that style. The smaller style, such as used on a John Deere, IS being reproduced, but that one will not be correct for a '39 M.

Anonymous-0 · Dec 2, 2010

Thanks Rusty. I just left the gen shop and they said it is a
cutout. They are going to check everything out. They said
they can fix the CO and mount it on the generator.

Bob M · Dec 2, 2010

Yours could be either (CO's with 3 terminals do exist). Best way to tell is to pop the cover and peek inside. If you find a single relay it's a CO; 2 relays = VR.

Which is best? VR, far and away. VR keeps the proper amount of charging current going to the battery. More importantly, a VR prevents the battery from being overcharged/boiling dry.

Unless you are a stickler for originality go with a VR!

mkirsch · Dec 2, 2010

It's easy to not get shocked by the magneto...

DON'T TURN THE SHAFT!

People get nailed because they grasp the magneto by the distributor cap with their left hand, and start turning the input shaft with their right. ZZZZZAP!

It's funny as long as you don't drop the magneto on the concrete and break it.

Magnetos don't store charge like a TV tube.

gene bender · Dec 2, 2010

The cut-out will work just fine if all things in the charging circut are grounded. You have three terminals one is the batt from the sw the gen terminal goes to the A term on the gen and the Field goes to the Field on the gen. Then a wire goes from the Field terminal to the lite sw at the bottom of the sw then the H position will provide hi-charge. With the mag you dont realy need hi-charge unless you are just using the tractor for short times as your batt could get weak from many starts. Is your gen still original and has the original tag.

gene bender · Dec 2, 2010

The cutouts used on all the I-H had three terminals Bat,Gen and Field and Gen and Field were hooked to the Gen.

Anonymous-0 · Dec 2, 2010

The mag if it is an H4 will have a distributor cap opposite the drive end and coil cover on top with one lead pointing toward the distributor cap. If you turn turn the drive end and it impulses there is a charge out of the coil lead. Don't impulse the mag without a wire from the coil lead or the distributor going to the frame of the mag. Set the end of the wire about an 1/8" from the frame of the mag. It should spark that distance. These things aren't deadly just hurts a bit if you get bit by one.

Anonymous-0 · Dec 2, 2010

Well I ended up having the gen shop set it up with a voltage regulator and had them set it up for an 8 volt battery. I got it all put back together and bought a new 8 volt battery and it wouldn't turn it over well at all. I checked the battery and it was not fully charged as promised by the guy at the gen shop. I got to thinking about things and I remember the guy that I bought it from telling me that he used to pull with it and he had some pretty spendy valve work done along with putting in M+W jugs. I suspect that the compression is plenty high causing it to be hard to turn over. That would explain why they were running a 12 volt battery in it even though it was set up for 6 volt. We'll see how things go after I get the 8 volt fully charged. I may end up having to convert it to 12 volt yet. I hope not I just spent the money on the gen, regulator, and 8 volt battery.

evilboweivel · Dec 2, 2010

replace all your battery cables and make SURE all connections are clean
6volt needs heavy cables not smaller ones for 12 volt
good luck
Ron

Anonymous-0 · Dec 2, 2010

Thanks but I bought heavy gauge cables when I bought the battery.

armand tatro · Dec 2, 2010

Please do yourself a favor and take all that 8 volt stuff back for a refund as fast as you can and get your money back!!! That conversion did not work 50 years ago when those tractors were new and does not work now!!!! With the engine upgrades you say you have You need a fair sized 12 volt battery with at least 750 cca and 12 volt alt. to spin that engine. As long as you do not abuse the 6 volt starter it will handle the 12 volt battery for many years unless it now needs to be rebuilt. What do you plan to do with this tractor? 12 volts is the only economical way to go. That and good cables and Clean connections. Use it and enjoy!! Armand

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