1953 M38a1 Hard start, engine stumble

[Oddjob807]

Hi everyone,

Sometimes engine turns over but won't start and on other days she will fire up. She can run like crap one day and another day she will run ok but with an occasional stumble.

On days she won't start at all, I can remove a spark plug and put a little gas in the cylinder and she will fire up. Engine will run albeit with a stumble every now and then.

Choke inspected and works and is fully choked when I try and get a no start.

Here is some background in case it is relevant:
All spark plugs replaced.
New cap and rotor.
New ignition coil.
Running 24v with Pertronix.
Carburetor is the original model and was a rebuild from Army Jeep Parts but has been opened and inspected by a local shop for blockages from possible fuel contamination. (all fuel lines replaced and fuel filter now installed).
Fuel pump was rebuilt by local classic car shop but it appears to be leaking oil.
Timing has been checked. At operating temp, she is running a little advanced. About an inch away from 5 degree mark. I can't physically turn the distributor any closer.
Compression test ran last week. All between 100-110#. Wet compression test increased the numbers only slightly all going up anywhere from 2 to 10#.

I've run across comments here talking about vacuum lines from the fuel pump can affect rough idle. Is this worth giving a hard look at?

I appreciate any help, thanks!

[4x4M38]

First thought is you need to reclock the distributor.

Second, why do you have oil leaking from your fuel pump? Is the pvc valve installed backwards? Do you have oil in your crossover tube?

More experienced minds will undoubtedly chime in, but that’s where I’d start.

[wesk]

OK Oddjob,

You have been kicking this ball around for some time. I know I weighed in on your posts before. Again, looks to me that a lot of spendy parts replacement troubleshooting has been done instead of following the troubleshooting charts in the manual in ORDER ORDER and record the result ON PAPER for each item. These troubleshooting charts are engineered to start with the simple cheap stuff and work forward. Problem is most heavy thinkers find the simple checks unimportant and skip to what their supermind thinks is a more appropriate starting point or they simply start what is called in this industry/hobby SHOTGUN TROUBLESHOOTING where they ignore the manuals and move on to those super sites like facebook and start trying anything that is mentioned having no idea if it is a valid step or if the poster has any mechanical talent. With that said, lets try to start over step by step this time!

Pick up your TM 9-8014 and start with the troubleshooting chart on page 80 par. c Engine starts but will not run. With a clip board and a piece of paper start recording each result.

(1) Air cleaner restricted or dirty. Now if you have a standard stock air cleaner open it up and inspect it's condition. Make sure the oil basin is not over-serviced! As you work your way to (6) if you have any doubts about your knowledge level vs the task just go to the manual page that discusses that parts disassembly and inspection. When you finish question (6) come back here and tell us the results to each step. Don't allow yourself to be suckered in by many folks that nose in and say check this first and try that first. That is not how a pro troubleshoots a problem. But is is how an amateur spends a lot of money! We await your first section review!

[RonD2]

Wow.

[RonD2]

That was OddJob's second post ever (by his post counter).

I wonder how he did.

On the other hand, I guess I don't blame him if he never comes back to tell us.