Bad Coil Update!
 

After following Rob Love's electrical diagnostics on my 67' M38A1 I finally have it running....after checking the plug to engine block for spark, coil to engine block for spark and other diagnostics provided by Rob I replaced the condensor and that was it ....the jeep now starts fast and runs smooth. While everthing was unbuttoned, I also checked the points gap (was good) and adjusted the fuel/air ratio. All is well.

Thanks Rob,

les

It is all common sense diagnostics, but when you start to get flustered, common sense and analytical thinking can get lost.
Glad it worked out for you.

Hi Rob....your so right....I was flustered in may ways and one of them was that all the diagnostics outlined in your email should have take a few hours....yet, it turned out to be several days as my helper kept dissapearing and I never knew when he would show up to crank the jeep over. As well, the small screw that tightens the condenser to the distributor slipped out of my fingers and got lost in the distributor...found, jumped out of my fingers again and got lost on the floor for over an hour....yup, its Miller time! But, it all worked out for the best. I have documented the start but no run issue in detail, the step by step diagnostics involved and finally the part I replaced for future reference.

All is good....thanks Rob!

les

I think I said condensor lol…

Your Right...
 

Hi Chris....yup...your right...you did say that it was most likely the consensor...as did the M38A1 manual....(or out of fuel)but why? How did you come up with condensor based on my "starts fine but runs rough and misfires"?

That said, Rob taught me to diagnosis the problem through testing & elimiation to lead to a conclusion of which I much appreciated. I assumed that you have been throught this issue before and knew the problem from the start. Again, based on what I said how did you come up with condensor....what part of the "starts but runs rough" problem lead you to your conclusion?

Cheers to you both for educating a pedestrian like myself.

les

Experience and solid understanding of how it works, so how to diagnose is something you need. Yet despite that these old beasts can do strange things that defy all of that and you never saw coming. It's only after days of pondering and finally finding the problem you say "OK, that makes sense NOW!!!" To be fair many problems are failures of parts that were never meant to operate 80 years after they were manufactured. In my dreams I'd have a room full of spare parts such that if something stopped working you could just replace things one at a time until it ran again.

Hi Les
Experience, been there, done that.
Have a good one!

Just a little helpful hint here. Points normally stay fairly clean, but when the condenser fails it sometimes leaves the points a little blackened. If you know to look for it, it can help with the diagnosis.

Thanks for input everyone..
 

Thanks for your input Lynn....I did check the points and they were as clean as the day I put them in ....in 2020 and about 1500 miles.

Interesting, after my initial start but no run issue...before looking at the manual & trouble shooting section and before posting on MLU my first thought drifted to fuel delivery so I checked the fuel pressue/delivery by pulling the fuel line after the two inline filters and just before the carb by cranking the engine....fuel spurted into a freshly empty coke bottle....my thoughts never drifted towards an ignition problem as I replaced the points, condensor and coil in 2020...go figure.

les

See, here's where experience kicks in. A freshly emptied beer bottle will preform much better.