Checking fuel pressure

Bobber · Post by **Bobber** » Tue Jan 19, 2016 2:00 pm

Working on 52 M38 with all stock original parts or rebuild kits from Midwest Military. What kind of pressure Gage would I use to check my fuel pump? I think I'm getting too much pressure to my YS 637 carter. I know I need to tee in right before the carb, but I'm unsure of what type or kind of Gage. Or the needle and seat valve are not stopping the fuel. It floods out real quick, I have pipe plugs in place of priming nozzles. So I can pull the plugs and blow compressed air into the intake and evacuate any fuel build up. Then she starts up right away. I get about a half a cup out when I do this. I'm still in the investigating mode right now.

Thanks. Rusty

RICKG · Post by **RICKG** » Tue Jan 19, 2016 4:12 pm

A typical eng vac/fuel pump tester.

Bobber · Post by **Bobber** » Tue Jan 19, 2016 6:29 pm

Thank you.

Post by **wesk** » Tue Jan 19, 2016 9:33 pm

Bobber,

Keep an open mind when troubleshooting. Cracks in the carb's bowl can allow raw gas to flood the manifold. High fuel pump pressure can allow the carb inlet needle to be forced open. A stuck heat riser valve on an M38 can cause perculation of the fuel in the bowl pushing it into the venturi. Float height setting too high can cause the flooding as well.

Bobber · Post by **Bobber** » Wed Jan 20, 2016 12:38 am

Thank you, good to know. I've been chasing ghost trying to find my problem. With the process of elimination, I've ruled out the distributor and or timing components. It runs well, but just not for long. I will keep these things in mind. I need some info for when I ask questions in the future. Sometimes I'm not sure which questions I'm to ask

Thanks

scoutpilot · Post by **scoutpilot** » Wed Jan 20, 2016 3:57 am

Is there a spacer between the pump and block?

Bobber · Post by **Bobber** » Wed Jan 20, 2016 10:39 am

Yes. I put everything back to close to original as possible.

Thank you.

Post by **wesk** » Wed Jan 20, 2016 7:50 pm

Keep in mind that the civilian CJ3B/CJ5/CJ6 fuel pumps do not use the 9/16" thick military spacer.