Vapor lock issues?

[Irishman999]

I have been trying to chase down a problem with my 305 hesitating off the line and occasionally losing power for a second and then it coming back. I thought it was the carb so I switched to a Carter AFB, stabbed in a brand new distributor and rebuilt my carb.

This problem is only happening when its been running at operating temp for a while, when the ambient air is warmer it runs worse. fuel pump is a new one from Orileys. Anyone have any thoughts?

 

[skysurfer]

Coil?

 

[89Suburban]

I don't miss trying to figure that **** out. Is that an HEI or separate coil? I agree with skt to try that.

 

[animal]

Actually had a simular problem after I put my headders on. The fuel line ended up actually sitting against the header on the passenger side headder and was basically boiling the gas in the line.

 

[crazy4offroad]

Adjust the accelerator pump for a longer throw on the carb, see if that helps. It may be running a little lean, too. Might need to re-jet to the rich side.

 

[Irishman999]

Cant be a coil, I just put a brand new distributor with a new cap and coil. I adjusted the accelerator pump and no difference. The next thing I was going to try is exactly what C4 mentioned, change metering rods and fatten it up a little.

Im wondering... It cant be leaned out if its running fine at operating temp with the choke open. Its only after driving around for a while it starts.

Has anyone ever herd of new fuel pumps vapor locking? I had a brand new fuel pump on my colt that would vapor lock like crazy.

If I wrap aluminum foil around the fuel line and it still does it maybe I should try another fuel pump?! I dont know. Its driving me crazy.

 

[crazy4offroad]

The next thing I was going to try is exactly what C4 mentioned, change metering rods and fatten it up a little.

Im wondering... It cant be leaned out if its running fine at operating temp with the choke open. Its only after driving around for a while it starts.

If it doesn't do it at idle, your idle air screws are right, but driving around the metering rods/springs/jets come into play. The plugs might tell the tale the best. If they look "really clean" it is probably running lean. I didnt think changing the accellerator pump travel would cure it, but it takes it out of the equation. Steady throttle tells me it could be the metering rods/etc. Otherwise there could be a vacuum leak but without backfiring issues I doubt that's it too. It would be easier to run a vacuum test than to start fiddling with the carb though.

 

[Irishman999]

Maybe it is a vacuum leak..... that would make sense. I've been talking about getting a gauge for way to long now.

 

[mrt]

Have you tried a heat sheild and a phenolic 1 inch spacer? That might help.