Running out of fuel at 2500 rpm

The 1966 V6 CJ5 runs out of fuel when I run it in any gear near 2500 rpm, as I slow down it will begin to come back, or if I push in the clutch it will go back to idle or I can restart. It will do it hot or cold, so I think that rules out vapor lock.

It ran fine till this started happening last week.

First thing I did was replace the fuel filter. The fuel pump was new and has less than 500 miles on it, no fuel in the oil. The carb is a Rochester 2 jet. Bowl appears clean. What else could be causing this? accelerator pump, float settings, ????

It runs fine if I keep it below 2300 rpms, I can run over 2500 rpm in neutral and it will not run out of fuel.

Thank you

 

Vacuum leak, check your gaskets.

 

collapsing rubber fuel line?

 

Bad fuel pump or float needs adjusting. If the float is too low it could starve at higher rpms, but I'd suspect the fuel pump.

 

how much fuel pressure you have?

the factory says 2.5psi. but mine used to do the same thing after driving for about an hour, till i upped the pessure to 3psi.

 

Fuel lines are new with less than 500 miles, I have checked for a pinched line and there appear to be no leaks, but will double check.

What are the float setting specifications? I can check as that was one of my thoughts, but how could it have changed? It was running fine before this.

Fuel pump? I'd be disappointed if it only lasted for 500 miles, but it might be worth a shot. I do not have a fuel pressure gauge, so I can not check it.

I'll check for vacuum leaks, have not done that yet.

 

What everyone else said. Might also check for a restriction at the fuel tank outlet. Could've got some foreign material in ther restricting fuel flow. You could do a volume check very easy without a gauge. Use a quart bottle of some type. Disable the ignition so engine won't start. Disconnect fuel line before carb but after fuel pump. Crank engine over with the fuel line in the jar. Should be a strong flow of fuel, not sputters or low volume. Should fill the quart jar in a minute or less. If not then flow is restricted or pump output is low. If you can't find any other problems and pump output is low I'd remove the pump and check the eccentric that runs the pump. It could be worn.

 

I was having the same problem with mine at the end of a recent jamboree. I thought maybe my pump was shot but no gas in the oil. Then I thought vaccum issue. I need new lines anyway. I did have some debris in the lines before but now they is none. The other day the JEEP ran fine with no hessitation. The filter was full also. Seems to have fixed itself. :? Oh well. Good luck with your fuel issue and keep us posted.

 

Put electric pump on in place of mechanical, still the same, fuel pump OK.

Fuel lines are mostly steel, and also new. Rubber only at tank, pump and filter.

I'll get a carb rebuild kit and drop the tank as the next two items to check.

 

x2.

 

Long rubber lines are a fire hazard. DAMHIK - not my car.

Steel good.

 

x3

 

Re: Running out of fuel at 2500 rpm - SOLVED

One of the rubber fuel lines was collapsed internally.