Tune-up

[capefarm]

After posting an earlier question about starting being difficult, several responses urged doing a tune-up, and since it had been awhile (and perhaps more because I didn't do a tune-up after buying it in 2017), I took the advice. So I watched Rachel's Cub tune up video and ordered the parts needed; however, after taking the distribut0r cap off, I saw mine was unlike Rachel's, probably because it was from 1949. I did find a video on how to static time this model, but I'm wondering if it's possible to get a new rotor. The condenser and points are the same. Even better would be to get a later model distributor, and change to a coil, but I don't know if it will fit the existing old J4 magneto. Any insights would be appreciated.

[Waif]

All that hard grease don't look good. I'd at least clean the gear teeth in thier valleys to be sure that's not hard.

Yes you can get a new rotor. Not cheap. But look how long yours lasted. If you get eager to run it before a new one arrives you can dress and clean your old one a little. Just enough to brighten top contact and the edge that allows electric jump to cap towers. Check cap tower contact areas too. Clean and dry. Clean and dry surfaces.

Tilting mag as instructed in maintenance manual works for timing.
Your tractor your business about converting it to external coil ect.. I wouldn't because stock configuration works. IF components are up to par.

[Jim Becker]

Don't pay much attention to what Rachel has to say.

[Barnyard]

Don't pay much attention to what Rachel has to say.

Personally I don’t pay any attention to what Rachel says.

[ajhbike]

Putting aside what she says, I have liked and learned a lot watching her videos...at the very least to see the parts and learn the names....when I started I knew how to change the oil in my truck and that is all I knew...and I suspect I am not alone.

[Glen]

Hi,
TM Tractor at the bottom of the page has new points, condenser, rotor, rotor drive gear, and cap for the J 4 magneto.
All Cubs came with a magneto up to serial number 115403, which was in 1950, then the Battery Ignition unit came out.
If the rotor gear teeth are ok, maybe you can sand the metal parts of it that are burned, and use it more.

http://www.tmtractor.com/new/el/294fp.htm

http://www.tmtractor.com/new/el/el_001newparts.htm

The rotor and its drive gear can get worn teeth, then they need replacing.
The gear area needs cleaning and new grease put on the gears occasionally.
Be sure to align the timing marks on the rotor and gear. Below is a picture.

[staninlowerAL]

After posting an earlier question about starting being difficult, several responses urged doing a tune-up, and since it had been awhile (and perhaps more because I didn't do a tune-up after buying it in 2017), I took the advice. So I watched Rachel's Cub tune up video and ordered the parts needed; however, after taking the distribut0r cap off, I saw mine was unlike Rachel's, probably because it was from 1949. I did find a video on how to static time this model, but I'm wondering if it's possible to get a new rotor. The condenser and points are the same. Even better would be to get a later model distributor, and change to a coil, but I don't know if it will fit the existing old J4 magneto. Any insights would be appreciated.

Your picture shows a magneto ignition and as you learned the battery/distributor ignition is a different part with a few parts common to both. IH sold a battery ignition conversion package for tractors (part #353 943 R91 for Cub tractors), and the Owner's Manual for installation can be found at the Quick links tab at the upper left corner of this page, pdf manuals. It contains complete information on changing from a magneto system to a battery ignition system. If you are contemplating changing yours, note that the mounting base that fastens to the engine is different and the battery ignition system will not mount on the base for a magneto ignition system.

[SamsFarm]

Even better would be to get a later model distributor, and change to a coil, but I don't know if it will fit the existing old J4 magneto. Any insights would be appreciated.

Just me, but if I have a tractor that has a magneto, then I am sticking to it.

I like the fact that I can start (with the hand crank) and use a tractor with a magneto and without a battery!

You could pull the mag and replace it with a distributer.

I have a Cub with a mag that someone bypassed the magneto coil and added a regular battery ignition external coil.

Never looked into it to see what is up with it, and why they did that.

[Barnyard]

I have a Cub with a mag that someone bypassed the magneto coil and added a regular battery ignition external coil.

Never looked into it to see what is up with it, and why they did that.

Many people will add an external coil when the built-in mag coil fails.

[Jim Becker]

. . .
I have a Cub with a mag that someone bypassed the magneto coil and added a regular battery ignition external coil.

Never looked into it to see what is up with it, and why they did that.

Because the internal coil went bad and a common battery ignition coil was cheaper or easier to find. It is a solution that combines the worst features of both systems into one package.

[SamsFarm]

It is a solution that combines the worst features of both systems into one package.

Lol! Only the best for me!

[phill_mi]

Just me, but if I have a tractor that has a magneto, then I am sticking to it.

I like the fact that I can start (with the hand crank) and use a tractor with a magneto and without a battery!

[ajhbike]

Ditto too. I have one tractor with a mag and when they are good, they are great

[Glen]

Hi,
capefarm, I sent you a PM, you get to it at the top of the page.

If you are contemplating changing yours, note that the mounting base that fastens to the engine is different and the battery ignition system will not mount on the base for a magneto ignition system.

Stan, I don't understand what you are saying, the magneto comes off the engine as 1 piece.
The Battery Ignition unit does have a casting that is the base, but the magneto and the Battery Ignition unit both bolt on the engine in the same place, and either one uses the same drive made on the governor gear.

[staninlowerAL]

Glen, I did not get your PM. To clarify, if the magneto is removed and intended to be replaced with a battery ignition system, note that the latter is a two piece part (distributor and base) and both mount to the engine in the same manner and are driven by the same gear/connection as you pointed out. The point being if a battery ignition distributor is to be used to replace the magneto be sure that BOTH parts of the replacement unit are available. BTDT, Sorry for the poor explanation.