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It's Dead!

Posted: Thu May 26, 2016 4:37 pm
by timjuhl
Long time no post. Since I restored my M38A1 in 2013 it has been running great and getting a lot of use.
Last weekend I drove it 18 miles to our local airport and spent the day giving tours of the grounds as part of our open house. Afterwards, I was three miles from home when it suddenly quit. No sputtering, just dead. I towed it home and finally got the chance to start digging into it today.
1.) It turns over fine
2.) I have 12 volts at the coil (12 volt system) and spark
3.) fuel is getting beyond the fuel filter
4.) When I disconnect the output of the fuel pump and turn the engine over with the starter, no fuel comes out!
a.) I had the military-type fuel pump rebuilt as part of the restoration.
b.) I pulled off the top of the pump and inspected the diaphragms and they looked fine. I see no obvious issue with the pump.
c.) I moved the pump actuator by hand and the center shaft moved up and down.
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Am I missing something here? I'm thinking of buying an electric fuel pump tomorrow and seeing if I can get it to run that way. Any suggestion of other things I should look at?

Thanks for your help!

Tim

Posted: Thu May 26, 2016 9:06 pm
by wesk
Tim,

Remove the inlet line from the fuel pump. Gas should flow from the line if the tank vents are clear and the filter not plugged. It may take one or two pounds of air pressure to help the flow start or jack the rear of the jeep up. If fuel flows from the line freely the problem is the fuel pump.

Or Take a plastic bottle and add a hose to the cap that will fit over the carb inlet and fill the bottle with gas, turn it upside down and squeeze the bottle as you start the engine. If she runs the problem lies between the carb and the tank

Posted: Fri May 27, 2016 6:38 am
by oilleaker1
Check that your primary inlet needle and seat are functioning in the carb. Anything wrong with the fuel pump check valves too. Crap holding them open and if the spring steel fingers are holding the checks tight on the gaskets. John