49 Cub Wiring Help

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freefour
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Joined: Mon Aug 20, 2018 7:13 am
Zip Code: 62988

49 Cub Wiring Help

Postby freefour » Mon Aug 20, 2018 7:28 am

I have a 49 Cub. The wiring is a mess. Does anyone have a good wiring diagram and sizes of wires needed? I need to know what item goes to each screw on the back of the switch too.

It is all original with 6v positive ground with generator and regulator. Thanks!

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Glen
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Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
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Location: Wa.

Re: 49 Cub Wiring Help

Postby Glen » Mon Aug 20, 2018 5:17 pm

Hi,
Here is some wiring info.

It should have a cutout, or Relay, on top of the generator. They are not a voltage regulator, you have to select the charging rate you want, with the 4 position switch.
The Cub owner's manual explains it.

A 1949 Cub would have a magneto, unless someone changed it to a Battery Ignition unit.

Below is the 1949 Cub owner's manual. The experts on here recommend reading it. It has much info about operation, maintenance, and lubrication. There is a table of contents on page 1.
It explains how to use the 4 position switch on page 34, and there is a wiring diagram there also.
Page 59 in the manual has a wiring diagram.

http://farmallcub.com/rudi_cub/www.clea ... index.html

Here is page 34 from the 1950 Cub owner's manual, the wiring pic is easier to see.

http://farmallcub.com/rudi_cub/www.clea ... e%2034.jpg

Below are wiring diagrams for the original, 1949 Cub electrical system.
The 2nd diagram is one Barnyard posted, it shows wiring sizes. :)
Attachments
cubwire.jpg
Cub wiring Bill.JPG

freefour
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Joined: Mon Aug 20, 2018 7:13 am
Zip Code: 62988

Re: 49 Cub Wiring Help

Postby freefour » Mon Aug 20, 2018 8:24 pm

Thank you Glen.

The diagrams and manuals will be a big help. Mine is original with a mag. I think it has a voltage regulator instead of just a cut out. There are four terminals on it: F, GEN, L, and another one on the opposite side that isn't marked. I would guess it was Bat? The wires were cut off before I got it so I am unsure. Any ideas what the L is for? There are leads attached to each wire but I don't know where they went. It appears from the diagrams that I don't use the Field or F terminal on the regulator, correct?

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Glen
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Posts: 4308
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: 49 Cub Wiring Help

Postby Glen » Mon Aug 20, 2018 10:00 pm

Hi,
IH changed to the voltage regulator in 1950. They didn't use them on top of the generator, they were mounted beside the gen on a plate.

The regulator on top of the gen can be used, other people use them.

Below is a wiring diagram for the newer system, with voltage regulator. Usually on the 4 post reg, the middle post on the side of the reg with 3 posts is the Battery post. The gen post is the one on the other side. But look closely and see what yours says. Clean all the connections with sandpaper too, and wipe off all sanding with a clean rag.
I think the reg has to ground to the gen also, so sand it's mountings, remove any paint under the mountings.
The Field wire has to be connected like in the diagram below, it is different than with a Relay.

The light switch was different with the original regulator system, a 3 position switch. I think the guys on here have said the 4 position switch can be used, it then becomes only a light switch. I think the first 2 positions are both Off then.
Attachments
cubwiringlate.jpg

freefour
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Re: 49 Cub Wiring Help

Postby freefour » Tue Aug 21, 2018 10:31 am

Glen,

Thanks again. It's a four post regulator. I checked again this morning. Below is a pic. There was a wire going from the bottom terminal to the A on the generator. A wire going from the F on the regulator to the F on the generator. The BAT and L terminal wires was missing. My guess it goes back to the light switch? The diagram you attached looks different. Which way should it be wired?

I only have a 1 post switch since it's a mag. I am not sure how to wire the L terminal since I can't go back to the switch. Are there any diagrams for 6v pos ground with generator and a regulator?

Thank you for all your help!

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Glen
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Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
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Location: Wa.

Re: 49 Cub Wiring Help

Postby Glen » Tue Aug 21, 2018 4:35 pm

Hi,
You need to change the wiring some from what a 1949 Cub originally had, to use the voltage regulator.
The Relay system, and the voltage regulator system, had different wiring harnesses.

The A, and Field connections sound like they are wired right.
It won't work without the Bat connection being wired, wire that like it shows in the wiring diagram above, with the voltage regulator in the diagram, not the Relay diagrams.
The wire goes from the ammeter to the Bat connection on the reg.
The other side of the ammeter goes to the starter post.
Those wires should be 10 gauge, like it shows in the Relay system diagram above.

The L connection powers the Battery Ignition unit. I think the guys on here have said you don't use it with a magneto, when doing a conversion. So there is nothing connected to the post.

When you run it after finishing the wiring, look at the ammeter, it should show charge, after speeding up the engine some. They don't charge at slow idle speed.

The gen looks like it is out at the end of the belt adjustment. If you are going to use the Cub much, I would replace the belt with a shorter belt, while you have the hood off. They stretch and need tightening eventually, it might be the right belt, and stretched, or it might have been too long a belt to begin with. It needs to be about 1 inch shorter than it is.
The guys on here buy them at auto parts stores like NAPA.
TM Tractor at the bottom of the page has them too.

I can't see the fan belt in the pic, the fan shaft should be a little below half way up the mounting slots with a new belt.
It's a good time to oil the fan hub, while the hood is off. Guys on here have had fans seize from no oil.
Below is a page from the 1949 Cub owner's manual showing how to lube it. A clean, pump oil can, with new engine oil in it works good.

http://farmallcub.com/rudi_cub/www.clea ... age-28.jpg

freefour
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Re: 49 Cub Wiring Help

Postby freefour » Wed Aug 22, 2018 8:49 am

Thank you again, Glen.

I did most of my wiring last night. I found a couple of youtube videos also that show how others wired them. I think I have it mostly correct. I ran a 10 gauge wire from the BAT to one side of the ammeter and a 10 gauge wire from the other side of meter.

1. I also ran a wire from the fused switch up to the ammeter as I saw in the video, is this needed? (see pic)

2. You are also saying I should remove the L wire? I made one from the L terminal to the switch. (see pic)

Also note that this pic is old before I removed what was left of the old wire, there are new wires attached now.

I haven't tried to start it yet. I wanted to make sure I am doing this right since it's a cross between two different diagrams.

As for the fan, I will check that out tonight and get a shorter belt.

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Glen
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Posts: 4308
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: 49 Cub Wiring Help

Postby Glen » Wed Aug 22, 2018 4:32 pm

Hi,
Glad you are making progress.

Here are answers for your questions above.

Question 1, no that wire is not needed, if you are using a wire from the regulator L post to power the lights.

Question 2, Yes, you could use the wire from the regulator L post to connect directly to the light switch. It powers the ignition and lights on the Cubs with a Battery Ignition unit, so it can power the lights alone.
The guys were probably using that short wire from the ammeter to the light switch to power the lights, which is why I said before you could leave the L wire off.
It has to have one or the other wire to power the lights.

Remember to not connect battery power to the small post on the magneto.
The wire grounds the magneto to shut off the engine.

You have to take off the fan belt to replace the gen belt.
Page 27 in the owner's manual shows how, and shows the belt tension specs.

http://farmallcub.com/rudi_cub/www.clea ... age-27.jpg

You need sort of a thin, open end wrench to put on the 6 sided place made on the fan shaft, that turns the shaft, and unscrews it from the nut on the end of the shaft. Do Not turn the nut, it can break the casting holding the fan assembly. Keep the nut from turning, if needed, with a wrench.
Sometimes they are tight, put penetrating oil on the threads if needed.

You can see in the pic below, from TM Tractor, the 6 sided place on the shaft, it is just to the rear of the gen pulley.
Attachments
Cub fan .jpg

freefour
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Zip Code: 62988

Re: 49 Cub Wiring Help

Postby freefour » Thu Aug 23, 2018 8:37 am

That's just what I needed to know. I got it all done last night and seems to be working according to the ammeter.

The last question I have is the light switch. The first notch nothing happens (I assume that was for the generator with the cutout), the second the tail light comes on and the third the front lights come on. Is that correct? Seems like the fronts would work before the tails. I got it wired exactly like the diagram, just wanted to verify.

Thank you again!!

Jim Becker
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Re: 49 Cub Wiring Help

Postby Jim Becker » Thu Aug 23, 2018 11:25 am

In the second position, the rear light should come on along with the headlights on dim. In the third position, you should still have the rear light with the headlights on bright. Power for the dim lights goes through the dimming resistor (the round wound one) on your switch. If that resistor is broken, dim lights will be off. It could also be a bad connection at either end of the resistor or a bad contact inside the switch.


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