M 38 motor trouble

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
athawk11
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Re: M 38 motor trouble

Post by athawk11 » Wed Sep 05, 2018 7:23 pm

Not trying to insult you, but we had a guy at the 2A Page that had the exact same symptoms. Couldn't get it to idle below 1000-1100. He tried everything.

Turns out he rans the spark plug wires in a clock-wise orientation instead of counter-clock-wise. In either direction 1 and 4 will still fire, so you can get the engine to run...but you can't get it to idle worth a darn.

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Re: M 38 motor trouble

Post by artificer » Wed Sep 05, 2018 8:54 pm

Sounds like a simple, easy to address/check & part toward a diagnostic plan!
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Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: M 38 motor trouble

Post by mdainsd » Thu Sep 06, 2018 6:45 am

dpcd67 wrote:
Wed Sep 05, 2018 7:33 am
Back to my original answer; I do not like, nor trust, the vacuum operated carbs. They are works of sorcery and demons.
I couldn't agree more! The spawn of Satan I say! Unfortunately I have an M37, 2 M38s and 2 WC dodges all using those cursed devices! :twisted:

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Re: M 38 motor trouble

Post by Ben Dover » Thu Sep 06, 2018 6:55 am

And all the M-38's and M-38A1 Jeeps I maintained in the military and the M-38A1 I have owned and driven since 1975 ran like Swiss watches.
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dpcd67
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Re: M 38 motor trouble

Post by dpcd67 » Thu Sep 06, 2018 6:59 am

I take it you never had to restore an M38 that had sat in a swamp for the past 40 years either. Those do not run too well.
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Re: M 38 motor trouble

Post by Ben Dover » Thu Sep 06, 2018 7:05 am

No problem, one has to start somewhere and be willing to invest the time and money necessary to recondition whatever is necessary, been doing this to Jeeps for 60+ years.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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mdainsd
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Re: M 38 motor trouble

Post by mdainsd » Thu Sep 06, 2018 7:36 am

Good for you. Im a newbie at this having only done it since 1968. I have yet to see ANY of these vehicles run with one of the vacuum actuated carbs run as well as they do when they have a regular carb sitting on top. Then again maybe our definitions are different. I cant stand a single pop or stutter period. I have a couple of M38s, the one that has a civilian 8 patent carb on it right now, truly running a well oiled sewing machine. Swap the mil carb back on and it isn't the same vehicle.

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Re: M 38 motor trouble

Post by Ben Dover » Thu Sep 06, 2018 10:26 am

If I could not make an M-38 or M-38A1 run like it left the factory, I would park it. The M-37 has a conventional carburetor with an accelerator pump plunger.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

mdainsd
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Re: M 38 motor trouble

Post by mdainsd » Thu Sep 06, 2018 11:42 am

Ben Dover wrote:
Thu Sep 06, 2018 10:26 am
The M-37 has a conventional carburetor with an accelerator pump plunger.
No, actually they don't. Please review a Carter ETW1 carb diagram. While it does use a plunger type accelerator pump, it is vacuum operated, not linkage operated as would be in a conventional carb.

JMZ421
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Re: M 38 motor trouble

Post by JMZ421 » Thu Sep 06, 2018 5:18 pm

I say if you do not want problems maybe go buy a new Jeep. It's a hobby and I have problems on occasion but I would not give up my M38 for nothing.
Great vehicle and has original carb and fording and I've learned to keep things tightned and leak free. No big deal, I work full time and still manage with my limited knowledge. I just hope these old timers hang around for many years to help me out John

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Re: M 38 motor trouble

Post by Ben Dover » Fri Sep 07, 2018 6:08 am

Sharing experience is what it is all about, and if one is going to preach factory or Army Maintenance, it is best to set an example. It works for me and the result is happy motoring and a trip back in time with an MV..
I realize that most Jeep owners are not Jeep service school mechanics, and do not have all the expensive tools.

Headed for the operating table in just a few minutes, hope to be back soon.
Happy Jeeping. :wink:
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

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