Motor missing

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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James L
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Motor missing

Post by James L » Thu Nov 28, 2019 7:53 am

We have 120 lbs. on each cylinder idles smooth but have a miss on no. 3 when we rev it up!!! New plugs new wires new cap new carb valves look like they are all working. Any help on this one would be appreciated. Thanks jim

junking
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Re: Motor missing

Post by junking » Thu Nov 28, 2019 9:15 am

Assuming you have checked for consistant spark on #3 while it is running. With insulated pliers can pulled the wire off the plug while running to see how much it effects the idel running. If only minor difference, may check the following:

Try cleaning plug threads and seat to make sure you have a good ground.

May also try swapping #3 wire with another cylinder to see if miss follows, if not, do same with the plugs.

Make sure no play in your distributor bushings. Could cause a miss. Not sure if that could bring a random or consistant miss.

Just a few ideas. It's all a process of elimination.

Good luck.
Military:WC-1, WC-3, WC-62, 1952 M37
Civilian:31 Model A, 41 Pontiac, 56 Chev, 1966 Mustang

JMZ421
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Re: Motor missing

Post by JMZ421 » Thu Nov 28, 2019 9:31 am

The manual states one of the things could be improper valve adjustment. But, you do have good compression. John

James L
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Re: Motor missing

Post by James L » Mon Dec 02, 2019 1:10 pm

Talked to an old Willys Jeep dealer. He said I can tell you right now wats wrong. !! The rocker arm tube and rockers are worn out. he was 100% right with lots of play the whole thing jumped all over and throws off the time.

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