COIL seems to have gone south (NO SPARK) - thoughts on bad coils in M151 Mutts?!

[DDTrustee]

NEW coil for a M-series (M151) Mutt needed?….slowly dying ignition?? No spark at all now – plenty of fuel. What went wrong? How to fix/
Heard coils are not reliable and go bad when they get hot? Or? Thoughts? Information? Checking threads on this!
Where to get a new coil for the distributor of the M151 so I can get the owner back on the road for his Father-Son trip from VA to NM back to VA via Roswell and Texas. Now skipping AZ.

[Rickf]

Well, You have found out the hard way about old 24 volt military coils. They go bad and short out. The even worse news is they are impossible to find NOS and if you do find one it is going to be both ungodly expensive AND at least 40 years old. The first generation of Chinese import coils were total garbage, most failed within a week if they even worked out of the box. I have heard that the second generation was much better made but I have not gotten any first person reports on them as of yet. It has been over a year since they come out with the second group of them, or at least the ones that were ordered by Reomie in Holland. So that could be good or bad. Just don't know. Red River Surplus should have the same coils since he is related to Reomie. All I can say is get one from Blake at Red River. Personally I keep at least two on a trip as spares.

[sjtrucks]

Anyone bought ones made for the Turkish army? I won’t be surprised if they are actually made in China, but just maybe the Turks have a factory?

[markrdje]

I had 1, it lasted 1 year

[hambone]

Have you tried testing your coil?
http://www.g838.org/viewtopic.php?f=3&t=6222

[Rickf]

Anyone bought ones made for the Turkish army? I won’t be surprised if they are actually made in China, but just maybe the Turks have a factory?

Never heard of the Turkish coils. Any more info?

[Rickf]

I did find a guy I have bought from in the past still has some NOS originals, he posted here not long ago. Here is the thread, last post.

viewtopic.php?f=15&t=318306

[sjtrucks]

Anyone bought ones made for the Turkish army? I won’t be surprised if they are actually made in China, but just maybe the Turks have a factory?

Never heard of the Turkish coils. Any more info?

They are listed on fleaBay. I ordered one from the Turkish supplier and one from Barney’s Jeep Parts. BJP said he’s sold the coil through his local and online store and hasn’t had any complaints on the “imports”! So I thought might be worth taking a chance.

Other thought - there is a local shop that winds DC motors for elevators (yeah, just slightly bigger in size ). But what specs do I give them for a custom winding?

[Rickf]

You are going to have a company that winds DC motors do a coil? This ought to be good! Hey, if they will build them they will make money! The original specs are 5-6 ohms across the primary and 11,000-15,000 from the primary to the secondary.

[sjtrucks]

You are going to have a company that winds DC motors do a coil? This ought to be good! Hey, if they will build them they will make money! The original specs are 5-6 ohms across the primary and 11,000-15,000 from the primary to the secondary.

Doesn’t hurt to ask, like they say - you miss 100% of the shots you don’t take. Given the state of imports and NOS turning to jelly - there has to be a way out. Someone must wind coils for a living - isn’t like this mutt is the only machine on the planet that needs them

The coil in my Mutt is showing all the signs of dying. Over the weekend, my friend rebuilt the carburetor, fixed all the vacuum leaks (there were a lot!!), replaced the fuel lines (old ones weren’t up to grade), put in a new cap/rotor and reset the gap in the plugs. After some carb tuning, it drove like a champ for about 5 miles to my place. Next day, I drove it - died a mile from my place, again died in 2 miles and then finally made it back to my place after letting it “cool” a few minutes. So I am coil shopping now

The primary winding reads 6.2ohms and secondary reads 14.85 Kohms. But that’s just on the multimeter.

I am waiting for two new coils and set of new plugs. Already have wire adapters for putting in regular plugs.

[Rickf]

Those readings are pretty good for a coil that has failed repeatedly. I am not so sure it is the coil. Do you have electronic ignition? That can do exactly the same thing and give the same symptoms. And you are SURE it is lack of spark and not lack of fuel right?

[hambone]

I've seen them test good when cold.

[Rickf]

So have I but not after repeated failures. Then is when they start to show high primary readings or open secondary's.

[sjtrucks]

Those readings are pretty good for a coil that has failed repeatedly. I am not so sure it is the coil. Do you have electronic ignition? That can do exactly the same thing and give the same symptoms. And you are SURE it is lack of spark and not lack of fuel right?

Sorry for the delayed response. Fuel side is good - tank has plenty of gas, mechanical pump (new), rebuilt carb. On the spark side, I replaced plug wires and plugs over the weekend. Cranked and it wouldn't start - keeps misfiring almost as if there is no combustion after the first cylinder. So started testing spark by pulling out the plug wires - first cylinder, the spark was good but then the second wire was weak. Checked the coil, it was really hot. My guess is - the coil isn't recovering quick enough from the charge-discharge cycle. <Drumroll> .... and, a coil I had ordered last week from Barney's Jeep parts arrived this AM, thanks to USPS Will report in a few hours if swapping the coil fixed the issue.

Meanwhile, waiting for the coil over the weekend, I looked into replacing the 24V snowflake coil with a regular/universal 12V coil and power resistor. Wonder if anyone has tried that route if the aftermarket or NOS 24V coils have been unreliable?

I also have another coil, from Turkey, scheduled to arrive tomorrow and I sent the spare distributor that I had, to a shop in Sacramento, that will look into building me a new coil. Will post updates.

[sjtrucks]

Yep, was a bad coil. Swapped in a new coil and it started right away - no stuttering, backfiring or buckling under load. Runs better than it has ever before in the few weeks that I've owned it

And, Fedex delivered my Turkish made coil too. Will swap that in a few days and keep the Barney's coil as a spare. One thing does bother me though - after a few miles of test run, the distributor bottom does get warm/hot. Is it supposed to do that?