Made a mess of things!

[Jim Becker]

Mike, thanks for the reply. I have never private messaged anyone yet but just sent one to Jim. Hopefully I did it right.

Yeah, thanks Mike. I got the PM. Call me at the number in my reply.

[Tim in MN]

Daniel-san got help from Mr. Miyagi. Luke Skywalker got help from Obi Wan Kenobi. Today I got help from Jim Becker! I towed my poorly running cub to him and it took him about 10 minutes to have it running like a watch. The culprit was weak spark due to a non/poorly grounded external condenser. Easy-peasy when you know what you are doing! Not so much when you don't! When I began to have trouble with this tractor not running I didn't know squat about electrical and timing issues but thanks to all your help I am feeling much more comfortable with this stuff. What got me into trouble this spring was when I got the timing figured out and started the tractor, It ran perfectly for several seconds and died after I saw a spark come from the external condenser that was not secured yet. I thought I had a short that ruined my coil and the condenser. I have some used parts on hand so I swapped them out. I could get the tractor to run but very poorly. Because of the spark that I caught with the corner of my eye, I mistakenly thought the condenser needed to be insulated from the coil/tractor, hence the weak spark. Jim said he figured from the other posts in this thread that it would most likely be a simple fix and he sure was right. In the painting process I had lost the governor connecting rod and put one from a parts tractor in it's place. While working on the tractor Jim noticed the key was worn on the governor rockshaft so he told me how to correct that as well. Jim, thanks so much for your time and expertise- you are a true gentleman. I am so excited to enjoying this tractor again!!

[Jim Becker]

Many of you have heard my mantra. "It's a bad ground". And so it was. There were a couple other details that didn't help during the discussion here. The tractor is new enough to have started out with battery ignition. It now has a magneto. Furthermore, it is an H-4 magneto, not a Cub magneto. On top of that, the magneto has been converted to an external battery powered coil and condenser.

On arrival, it would start but run very erratically. We static checked the timing, which was dead on. Checked the positions of the spark plug wires, fine. Then checked the spark. There was one at the coil wire but very weak. Tim had another coil so we decided to swap them. When starting that swap, we realized the condenser wasn't grounded. Pulled the coil bracket and gave it a good wire brushing. Put it all back together and found a much-improved spark. (still not excellent, but pretty good). Plugged the coil wire back into the distributor cap and it ran like a top. There is one detail we never got to. Since it is an H-4 magneto, it probably has an H-4 impulse coupling. If so, when it starts and goes to full advance, it is a lot more than was intended for a Cub. It could be verified with a timing light. It is probably okay if the tractor is just going to do some light running. If it is going to be put to work, it should be changed. From what Tim said, I think he is okay with the current setup.

[Tim in MN]

Jim,
You are correct in that fact that this particular cub doesn’t get worked too hard, but I may hang the brush hog under it in the future. It would be nice not to hurt anything if I work it hard.

What would you recommend I do in this case? I have no idea what impulse coupling is?

[tnestell]

Impulse coupler lets the engine start with little or no advance and once started the distributor timing will advance.
Difference between a J4 and H4 magneto https://farmallcub.com/phpBB2/viewtopic.php?t=98570

[Don McCombs]

Jim’s recommendation may be different, but I’d replace the incorrect mag with a good, used proper distributor. You’re already half way there.

[Glen]

I have no idea what impulse coupling is?

Hi,
The impulse coupling is in the front of the magneto, where the drive couples to the governor gear's drive for the magneto.
The impulse coupling makes the snapping sound when the magneto turns at slow speeds.
It has a spring that winds and then releases when the snap is heard.


I think the majority of 1955 Cubs came with Battery Ignition.
It is a newer item than the magneto.
They have a built in spark advance that advances the spark different amounts at different engine speeds.
Here is what the 1955 Cub brochure says about them.

Battery Ignition has automatic spark advance to assure smooth running at all engine speeds and exceptional lugging ability.

Below are pics of one from TM Tractor.
The coil goes on top of it, using 2 brackets on a Cub, they are not in their pics.
TM Tractor sells the coil and brackets.

http://www.tmtractor.com/tm-tractor/gel ... or_001.htm

J P Tractor Salvage at the bottom of the page probably has a used Battery Ignition unit, if you want to put one on the Cub.
I would put new points in it before putting it on the Cub.

Below are pics, the first 2 from TM Tractor.
The 1st pic is the J 4 magneto for the Cub, it is smaller than the H 4, I think.
The 2nd pic shows where the impulse coupling is. It is under the cover where the 2 drive lugs are in the pic.
The 3rd pic shows a Battery Ignition unit on a Cub.

[Jim Becker]

Jim’s recommendation may be different, but I’d replace the incorrect mag with a good, used proper distributor. You’re already half way there.

I fundamentally agree with you. I really don't like the magneto converted with a coil arrangement. I think they combine the worst of both stock ignition systems.

However, there are some factors specific to this case. The existing magneto is full of new tune-up parts that can't be used in the Cub magneto or battery ignition unit. Besides, it is running great and who wants to mess with success? He might want to keep an eye out for a stock system in case he does decide to put a mower on and run it.

[Don McCombs]

He can always sell the H4 to recoup some or all of the cost.

[Eskimotom]

Hi Tim,
I can't help with your startup issue, but noticed you're in Central MN. I'm 30 minutes WSW of St. Cloud. If you have a minute, can you outline how and what you used to repaint your Cub? I'm currently repainting a yellow '63 lowboy, not a complete tear down, but I have the hood, fenders, seat, lights & little items separated. I replaced the plugs & rotor. Currently of final coats of primer, of an amateur effort. I carefully brushed the base of the tractor by hand & plan on spraying all the removed items.

[Matt Kirsch]

Jim,
You are correct in that fact that this particular cub doesn’t get worked too hard, but I may hang the brush hog under it in the future. It would be nice not to hurt anything if I work it hard.

What would you recommend I do in this case? I have no idea what impulse coupling is?

Not going to hurt anything. You're just leaving some performance on the table with the H4 magneto timing being too advanced, and with a Cub you need every drop you can get.

The impulse coupling itself isn't the issue. The magneto as a whole is, and it's not practical to change the timing advance on them as far as I know.

Not just any old IH distributor is going to work well, for the same raisin. There are different advances available and you will want one for a Cub.

[Tim in MN]

Thanks much for all the input guys! It's fun to learn about the stuff you have always avoided. I'll run her as is and keep an eye out for additional parts- nice to have a stash of extra cub goodies.

Eskimo- I have done all the prep work for a refurbished cub in the past and a friend shot the final coat on it for me. On this tractor I decided it was time to do it all myself. I had all the sheet metal and wheels blasted. I sanded these parts as the blasting left them too rough. For the rest of the tractor, I washed it down with a friend's hotsy and sanded it. I got rid of anything loose with a wire brush and left the good sticking old lead paint on with a decent sand job. I primed the tractor with a self etching primer I got at NAPA. This primer caused me a bit of trouble, I believe. Even though I scuffed the primer, the paint doesn't adhere to the primer as well as I would like. On the next tractor I'm going to restore I'm going to make sure the primer and paint are from the same manufacturer. For paint, I just used Old 55 I got at Fleet Farm. I personally like a brighter red for my cubs than what would be considered stock. I used their Gloss Case IH Red M45571 enamel paint. I also got my hardener from FF- Van Sickle A7019 6. For a thinner I used NAPTHA as it dries faster than mineral spirits. I painted everything outside and was very pleased with the minimal amount of inclusions in the final coat. The HVLP capsprayer I used blows warm air into the gun and I think this, in conjunction with the hardener and NAPTHA, dried the paint quick enough to help fight against anything sticking to it. I called the phone number listed on the paint can to get a couple questions answered and judging by the conversation I'm pretty sure I was helped by one of the owners of Van Sickle paint. He was very helpful but I can't remember his name.

This is what I did and I'm sure there are better methods/ ingredients. On the next tractor I'm going to restore I am contemplating using regular old Rustoleum Sunrise Red. Thinking it may be a bit tougher and easier to touch up if I want. Really like the look and fast drying of the Old 55 so I am going to try some samples of it with the more compatible primer.

I got a 3M respirator for the paint and a 3M respirator for dealing with the lead dust. i also bought a cheap white suit at Menards to keep the lead dust off my clothes. The work I did that released lead dust or paint chips was done in an area where I didn't have to worry about the family getting into it.

[Don McCombs]

Before you do any more painting with hardener, inside or outside, I would like to suggest that you read this thread in it’s entirety.

viewtopic.php?t=39149

[Jim Becker]

Before you do any more painting with hardener, inside or outside, I would like to suggest that you read this thread in it’s entirety.

viewtopic.php?t=39149

Don, while you were posting this, I was in the midst of looking up the same link to post the same thing.

[Indy4570]

just had a mental image of Jim sitting in the lotus position humming "ohm.. it's a bad ground...ohm...it's a bad ground...". "we are not worthy " says the group of weedhoppers....

great group of guys ( and gals! ) on this forum!