Pony problems on D4-5T

If you are getting a jolt from a spark plug lead, your points are probably fine.

Gap for the points on the Eiseman mag which was standard on these ponies is 0.014" to 0.018". My D6 9U book shows a Bosch mag (with an impulse coupling that the D4 pony never had), but anyway, it lists the same spec.

Your condenser might be weak, these are pretty much the same in many applications, so you could try one from an autoparts which has a similar lead and bracket to screw it down in the mag.

Also check to see if you can take a wire and hold it about 1/8" away from something for the spark to jump to and crank it over. If it'll jump that, your plugs may just be bad. Gap plug to 0.025" or maybe a little less if your mag doesn't throw a great spark. Sometimes removing a plug, dipping it in a little gasoline and burning it off (BE CAREFUL!) will get one to fire when it wouldn't before.

Best plug wires to use are metal/wire core, not the carbon fiber resister type. You can also have problems with the magneto cap or rotor button when a crack allows the spark to track across the insulator surface to ground. I believe these can be sanded/scraped out and coated with clear polyurethane to restore the insulation, or just replace the damaged part.

There is a listing for magnetos and service in the FOR SALE/WANTED section of this board (look at the little pull down box on the bottom of the pages), though I cannnot find it now. Here is the contact information from an old post on this board.......
"If it is your mag i rebuild them and also have exchange units for your machine call me at 309 923 7346 or email at
[email protected] Thanks Rick Fuller"

I would take care to record how your mag is timed before removing it, since all the instructions are for the Eiseman RC 2H mag which was standard.

Good luck!

There is a mag rebuild place in Chicago. Every once in a while some one complements them on thier work.

Thanks for the replies. I will try the clear coat of the cap and if any condenser of comparable size will work, I will try that also.
As stated in my original post, I have a Bosch mag. Can I assume the points gap is the same as for your Eiseman?
The Champion plugs that came with the machine look new but as I have read in earlier posts might not be acceptable. I have ordered NGK-A6 as recommended by someone on this board.
Ken

For such simple little motors, why are there so many problems with them?

Granted, they're 50 to 60 years old (maybe that's the answer).

I talked with someone at Standard Magneto in Chicago today about my magneto. He said if I sent it to them, they could diagnose and refurbish it with about a 2 day turnaround. We didn't discuss price, but there are some price lists on their website.

Phone # is 1-800-624-6386.

My spark will jump close to an eighth-inch gap (maybe it's closer to 1/16", but I thought I'd read elsewhere here that 3/16" to quarter inch is what you're looking for.

I'm thinking it would be worth sending, to at least eliminate that as one of my problems.

For years, I chased my pony motor problems. It would only run slowly with the choke pulled part way out. Then once it got hot, it would run worse. Then eventually it would only run fully choked, on one cylinder and poorly at that. I did the complete carb rebuild with drilling out all of the lead plugged passages and so on. It helped just a little. The pony motor soon ran even worse. I looked the mag over for cracks in the cap, used NGK plugs, and added solid wire spark plug wires. I replaced the condensor and filed and set the points, only to still have it run on only one cylinder and poorly at that. I sent my mag off to be rebuilt and it was the best money that I have ever spent on the D-4. They found a crack in my mag's cap and they replace the mag coil too. It now starts immediately and now it will also run with the choke completely turned off. The pony motor can now also run at any speed desired, and it is an entirely different cat. I now know when I shut it down out in the woods, that the next time that I go to start it, I won't have to screw around fighting pony motor problems. Color me happy. 😊

If you get spark, say enough to jump 1/8-3/16" and no fire, try switching the plug wires at the cap. When I have trouble getting one of these critters to pop off, I'll pull the plugs and squirt a little "goose juice" (ether) into the plug holes, put the plugs back in and try again. If no "pop" I'll switch the wires back and try again.

SSssssteamer,

If you don't mind my asking, where did you end up sending your mag?

My D4's mag was rebuilt by Industrial Electric and Machine Co.. Located at 1030 C St. Bellingham, WA, Telephone 360-733-4920, toll free 800-290-8848 They have been in business for over 80 years and they have the parts on hand, and the experience to do the job right. With in two days of leaving it with them, my magneto was rebuilt , tested, and ready to be picked up.

Hi there cat10ken.

Kind of interesting to see another person so close to me working on a rebuild for a D4 5T. I just went thru all the same things with the pony motor. I found a used mag on this site. You should be able to get another one here or have it rebuildt. I might be able to help you test it. My pony motor is still sitting on the bench. It is all put back together and runs. Just need to finish the dozer. Let me know if you need a hand. I am up in Necedah.


dratt