Tue Feb 03, 2004 7:56 pm

Hi again, I forgot to mention that it had a coil on it also. ( On the 12 volt system)

Tue Feb 03, 2004 8:49 pm

I sounds to me like you have the later style panel. In '48 the light switch was centered with the ignition switch directly below it. It changed to the style like yours in mid-'49. Likewise your light switch sounds like the one they started using in mid-'50 (same time the fuse was added). The one pictured in this thread was used until then. No '48 Cub came with a fuse holder other than the one on the light switch. If the tractor was equipped with any electrical equipment (lights or starter) it would have had an ammeter. Some were built with no electrical equipment.

Go to this page http://www.tm-tractor.com/gsu/gsu_001.htm on the TM Tractors web site to see pictures of each one. You can also look around on that site to see pictures of both styles of light switches.

If you have the later style switch, where is the wire from the generator F terminal connected? That stuff on the bottom of the switch is the field resistor and connections.

I still suggest you look here http://www.tmtractor.com/id/id_001.htm to verify what year tractor you really have.

The maximum output from the generator happens when the F terminal is directly grounded. This way it should (when warmed up) produce 9-11 amps at 7.3-7.6 volts. Both will be higher when cold. So your 7.5 volts was on the high side of normal. The resistor on the switch (if it was there) and the resistor connected to the cut-out F terminal are both 2.8 ohms. With that resistence in the field circuit, the output is limited to about 4 amps. With 1.4 ohms in circuit (as with both resistors connected) the output would be somewhere between 4 and 11 amps.

As John said, you can adjust your thirsd brush to change the output. But based on the measurement you took earlier, it looks like your is fine now.

Tue Feb 03, 2004 9:27 pm

I looked Jim at the sites you gave me. The panel is the syle 1 short wrap around The second one on the page. I also looked at the light switch and I have the 3 position lighting switch. So, my next step is to look at some of the numbers on the castings to find out what year it is for shure? Is there any place you look to easily find the casting numbers?

Tue Feb 03, 2004 10:01 pm


Tue Feb 03, 2004 11:12 pm

As illustrated on the page Jim Hudson pointed out (left of engine block). The engine number is stamped in just to the right of the carburetor. It is harder to spot since it is stamped in , not cast.

-on the bell housing, right, by the clutch pedal (usually partly covered by wiring),
- left side of Touch Control block
- inner sides of the final drive housings, above where the drawbar bolts on.

Wed Feb 04, 2004 7:57 pm

Maritimer, I've never seen a high crop cub, only pictures, so I would say to check out the parts dealers on the home page for those pieces. I expect that a high crop would have a serial# suffix also? Jim, Jim, John, you guys should be able to tell us? :?:

Wed Feb 04, 2004 8:25 pm

Jim, Jim, John and Rudi,

Oh boy, do I ever have a mess. My engine # is 10 25 W which makes it a 51,.Bell housing # is X 8 8 which makes it a 52, The hydraulic unit is 11 26 X and the tran is 8 12 X. Both which are a 52. Oh, the date above the draw bar bolts is also 11 24 X. Which is also a 52. So is it safe to say this is a 52 cub? Back to the original question, Is my generator correct? It has lights and stuff, do I have to put the ammeter in? What about the fuse on the panel? What wiring diagram do I use?
Sorry I'm asking so many questions, and being sort of redundant. But This is sort of new to me and I would really like to learn. I have 5 tractors so far. A 47 pony, a 58 JD A , 52 JD 40, 53 Farmall H and the !@#$% cub.
Thank you guy's for your help so far.


Thu Feb 05, 2004 1:28 am

I think the ammeter would be good. Don't now what gen was original but if your going to use one with cutout the print is listed in this thread on first page by John.

Thu Feb 05, 2004 7:55 am

It isn't unusual to see a fairly wide spread on the date codes, although over a year seems to be a stretch. I suspect your front casting got replaced with a used one that had a serial plate attached. Most of the rest of the tractor probably is original parts from '52. The late November dates could have pushed it into '53.

The original generator for the '52 time frame was one of the generators designed to work with a voltage regulator. The regulator mounted on a bracket below the generator. Your tractor is probably below serial 165153. At that time several changes were made including a larger generator pulley on the fan hub (requiring a longer generator belt). At that time several other changes were made including adding ground wires to the harness and probably the change from the teardrop headlights to the flat sealed beams.

I would think you would want an ammeter. Although things could work without it, it would be hard to tell. The second wiring diagram on page 2 of the ATIS Cub FAQ should work for you.

If you want to use your generator with cut-out, you will need to make a couple changes. Your cut-out has no L terminal, so connect the wire that goes there on the cut-out BAT terminal. Instead of connecting the short wire from the generator F to the cut-out F, run it from generator F to ground.

Sat Feb 07, 2004 12:59 pm

Jim Becker,

I wired it up like you have said. Do I have to create a ground for gen F to ground?
Also a guy here I was talking to said I should run a wire from ammeter + to the ignition switch. Is this correct? I'll take your advise. So there won't be anything on F terminal on the cut out?

Mike ?

Sun Feb 08, 2004 12:14 pm

You will have to make up a short wire to run from the generator F terminal to a ground. The mounting screw for the cut-out is a good place to ground it.

There will be nothing connected to the F terminal of the cut-out.

If you have battery igniton, the ignition switch will have 2 lugs. One connects to the coil and the other needs a hot wire to it. The hot feed can be from the same side of the ammeter that the BAT terminal of the cut-out connects to.