Case DC3 model 41 Magneto Intermittent Spark

[ChampagneNBeer]

Hi All,

So completed a little clean up work on the 41 Magneto and am getting an intermittent spark.

Only thing I have done so far is clean up the points and reset the gap to .015.

Can anyone chime in with next steps?

Measure high/low coil resistance and what numbers to look for?
Measure condenser resistance and what numbers to looks for?

How deep into cleaning should I go? Never torn apart a magneto so not familiar with cleaning/what to look for.

Thanks

 

[wore out]

The MOST likely cause of ''intermittent spark'' would be that the breaker points are still not making good contact all the time.

 

[J Hamilton]

I would call Kevin's Magneto Service 309-303-2634 He is very helpful and is who I send all mine to for repairs I can't do myself

 

[old]

I agree with wore out the point need more TLC

 

[ChampagneNBeer]

Ok,

So I completely took apart the magneto, cleaned as best I could and reassembled.

I now have consistent spark I can see when I hand turn the impulse but when I put the cap back on (new plugs) I get no spark on my test light- ugh

Two questions:

1) Anyone know of a way to test a magneto cap? (The graphite looks good and moves freely)

2) Can anyone tell me about the function of the two screws on the mag cap? One on the bottom has a thin piece of sheet metal going to the case screw next to it and the 2nd at the top with the curved washers? I am guessing the top one is for ground to cut off magneto, but unsure of the bottom one

I have all wires removed and unless there is a ground issue somewhere I cant figure it out.

 

[tractorguy2]

Parts are hard to find for the Case magnetos. There is a guy selling points on ebay. Ive had a few of his. They are not a perfect fit. To get the points set. I have to use my Dremel tool and drum sander and remove some material were the points hit the bushing for the rotor.

If you need a condenser. I have used condensers for International H4 mags. You will have to make the holes in the wire eyes larger.

The model 41 seem to have more coil trouble than the JMA. Coils for the 41 are not available. You have to send your old coil to a mag shop that has the ability to rewind the coil. it will be expensive. With a fair amount of fabrication, I have made coils for Fairbanks Morse mag fit in the Case 41. It's time consuming.

 

[ChampagneNBeer]

I think I figured out the issue - gonna check tomorrow to see

Basically I took everything apart, cleaned it as best I could, put it back together and when I hand turn the impulse I get an arc across the points BUT when I connect everything back up the tractor - no spark.

Had me first thinking about the rotor and the cap etc, but then I noticed the plate at the bottom of the cap (copper plate) is connected to a copper arm inside the cap which pushes on the point screw (connected to the coil primary wire).

Got me thinking this copper plate must be a manual ground shutoff but the previous owner who was saying he couldnt get it to run has that plate on the outside bottom of the cap connected to the screw for the housing.

Anywho - I hope I am right - but I think with that copper plate touching the housing screw it is grounding my coil and so I get no spark when it is all hooked up.

So tomorrow am going to bend that copper plate away from the housing screw on the outside and see if that does the trick - fingered crossed.