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overhauled engine - does not run 100% evenly

Posted: Wed Feb 12, 2020 3:20 pm
by pduske
I installed a completely overhauled F-head engine in my M38A1.
distributor was properly set - when idling, the engine is irregulary coughling.
What could be the reason?

- distributor camshaft worn out
- carburetor not delivering a constant air/gasoline mixture
- ?

I appreciate your help

Philipp

PS: The jeep accelerates good an without problems

Posted: Thu Feb 13, 2020 9:51 am
by jnissen
Have you adjusted idle mix screw? Verify ignition is up to snuff. Poor firing ignition normally shows up under load so acceleration good is an odd one.

BTW. When’s last time fuel was changed? If older than 30 days ethanol fuel will go bad as it absorbs water. Only gets worse with time.

One reason why we run non-ethanol fuel

Posted: Thu Feb 13, 2020 10:48 am
by wesk
Even a freshly overhauled engine should be thoroughly diagnosed by retesting it. Before you ask for folks to toss ideas out of the blue to you, try to help them understand the actual current condition of the engine. Perform the standard battery of tests and post the test

Vacuum Gage Readings:

Idle:
Acceleration:
Cruise:
Deceleration:

Compression Gage readings:

#1 -
#2 -
#3 -
#4 -

Differential Compressions (Leak Down Test) Readings:

#1 -
#2 -
#3 -
#4 -

Fuel Pump Pressure:

Fuel Flow Rate:

Float height setting:

Capacitance Test results for point condenser & radio filter:

Coil resistance test:

Cold -
Hot -

Generator/regulator performance:

These are the most common tests used for proper troubleshooting.