M38 help needed Boston Metrowest

[ramapoarmyjeep]

Greetings all:

need a good engine mechanic in my area (boston metrowest - natick holliston) who knows the 4-134, 24v w/ a MB carb setup well. My long time local guy has been great with many vehicles, but he and this one do not get along at all.

history: family has been running m38's for many decades, never hard to start. this one became hard to start in 2021. local guy rebuilt carb and replaced points. towed back w/in 2 weeks because would not start and massive gas leak. More carb work by local guy, still near impossible to start and always needs choke to run at all. "well, they are all like that" he says. "not for the last 45 years" i say. Dies again at his shop in April 2022 during inspection. More muttering by him about weak spark, he replaced coil.

Ran for a while earlier this year, but would never idle down and needed lots of choke (choke lever also advances throttle, of course). July started missing and bucking w/ no power up hill after a 10 mile run. I replaced dist lead with known good 24V. I replaced coil (again). I replace fuel pump and 4X new spark leads. now has spark for sure. new fuel pump has glass bowl so i know there is fuel.

Cyl #3 plug always comes out wet, even with diff plug. hmmm

Ran ok 3 weeks back then bucked backfired and quit at 2 miles. Another tow. hot day, maybe that was vapor lock

later, cooler, same thing, runs for a bit then backfires slows and quits. in most recent attempt, one backfire was so major it literally blew a giant hole in the muffler. not a hot day at all

i suspect some valve or gasket or other engine internal is off.

many thanks in advance for tips

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[OKCM38CDN]

I had problem years ago where the jeep would not run well, even blew the muffler up. Got it to start and took starting fluid and sprayed all over the place where leaks could form. Found massive leak at the manifold to head connection. Took both manifolds to a machine shop with new bolts and gasket and had them put them together and machine the face where the manifolds connect to the block. THis must be done with the two manifolds set up as one. Cost was $100 back then have had no problems since then...

Not saying this is your problem but is something top look at, possible vaccume leak...

[wesk]

How about running a few simple tests and record readings so folks can arm chair with adequate technical information.

1 - Compression test results.

2 - Leak down test results.

3 - Vacuum readings.

4 - Fuel pump operating pressure.

[whydahdvr]

I can't help with Metro-West but Dave Adario here in Melrose, MA is who worked on my M38 and my GPW. He's great and really enjoys working on the jeeps. Give him a call or check him out.
You can let him know I recommended him.
Josh

[ramapoarmyjeep]

thansk all for the tips!

Will chekc out the Melrose guy - and of course report back