M38 idle issues

[lee12]

I am having some issues with my m38. I have a rebuilt engine installed 1/15. Rebuilt YS and a new solex Carbs. I had the solex while I was waiting on the YS. The fuel pump was rebuilt by pete debella but sat for about a year while waiting on engine rebuild and I know it had corn gas in it before it sat.

The jeep has been running ok since the engine install with the solex and a fuel reg set at 2 psi. I was having some trouble getting the "popping out of the idle" but all in all it was running well. One day last week, I started it up and it seemed to be missing or fouled at idle. When running down the highway it ran fine just at idle it seemed to be missing. I checked the plugs and all were clean and gapped. reinstalled and same.
I got my YS rebuild back and installed it. It starts much easier with the YS but the idle runs smooth for a bit then runs very rough as if its about to die for a bit then it smooths back out for bit and so on. It agains runs great down the highway just no idle. And it still sounds like its missing or fouled at idle.

I haven't opened up the distributor yet but that was where I was headed next. Then I thought maybe I should check the fuel flow/output as well.

About the fuel flow, what kind of gage do you use to measure this with and how do you use it, being that the engine has to be on to work the pump.

I have the operator and engine manual, and Ryans m38 bible, and I know about the downloads on here which are great. I have been reading all the trouble shooting that I can find and Im sorry to bother you but I just cant seem to make it work.

[wesk]

About the fuel flow, what kind of gage do you use to measure this with and how do you use it, being that the engine has to be on to work the pump.

The most common test is by using a pressure gauge. The details are on page 78 & 79 of your TM 9-8012.

Before I started any massive troubleshooting and component swapping I would check a few basics. I would not initially suspect the carb since the problem was present with both carbs.

1-A low RPM air leaks in the plumbing will have a greater affect on fuel delivery than higher RPM's. Check all plumbing for loose fittings or small holes. Do not overlook the standpipe in the tank. They are notorious for corroding and perforating and when the fuel level in the tank gets below any of the pin holes it gets harder for your pump to suck the gas.

2-Make sure the tank vent pluming is not restricted and the filler cap is not in the fording position.

3-If you have the two fording valves under the hood make sure they are open! Corrected minutes ago!

[4x4M38]

Hi Wes,
Don't you mean the fording valves should be open?