1943 D4 2T pony motor

Hi Mark,
do you have a strong blue spark when pulling on the starting rope?

I do need to check that . have 2 mags both the same kind . I don't think parts are available for them . EISENDORF I think is how it is spelled. do they have an impulse for starting to.

Judging by that name, I'd suspect it's an Eisemann mag, which was used on the earlier D4s until Cat switched over to American Bosch. My 3J-D2 has an Eisemann and my 5U-D2 has an AB. Anyhoo, at your normal pony cranking speed i.e. what you get when you pull on the rope, you should have a decent blue spark (in dim light admittedly - they're a bit hard to see in bright light, so check it at dusk).
Someone will correct me but I don't think that D4 had an impulse mag (I only have D2s but I think most if not all of the pony arrangement is the same)
Things to check if the spark is weak:
- condensor (change this anyway)
- spark plug leads (must be solid copper core)
- spark plugs (change these anyway)
- distributor cover; you may be getting spark leakage along a crack or dirt

If none of those produce a decent spark, send the mag away for rehab (and borrow someone else in the meantime)
If you do now have a decent spark after attending to those matters, then we'll dig further.

I have an extra mag .the one on the machine was put on because THE ORIGINAL WAS WEAK . I well rebuild the other one that is actually the original for the machine . how many rpms does the mag spin I well make up a jig to test my weak one and fix it . I use autolite spark plugs . thing runs awesome once it starts ,don't think there are any carb issues .who is the best supplier for parts for these old mags or is there an easyier and more available mag to use .

I have an extra mag .the one on the machine was put on because THE ORIGINAL WAS WEAK . I well rebuild the other one that is actually the original for the machine . how many rpms does the mag spin I well make up a jig to test my weak one and fix it . I use autolite spark plugs . thing runs awesome once it starts ,don't think there are any carb issues .who is the best supplier for parts for these old mags or is there an easyier and more available mag to use .

Pony motor magneto input shaft turns same rpm as crankshaft, so the mag needs to perform at say 300 rpm while cranking to over 3000 rpm at full governed rpm.

Magneto has 2 to 1 gearing inside to drop the rotor rpm back to 1/2 crankshaft rpm.

In the sticky notes at the top of the screen is a supplier list. There are names and contact info for a couple of Mag Rebuilders that other members have had good success with!