Carb Problems?

[Rusty Shackleford]

I just installed a new fuel tank, replaced lines, had the carb cleaned, new carb kit used and now the P15 is rarely starting. When the car does start it runs rough and usually dies after a few minutes of rough idling. If I open the throttle it sounds like a ton of air is rushing in and it almost always dies, unless I let the throttle off, then it dies after a short stint of rough idling. I have set the float level to 5/64 like the manual states and the accelerator pump to 3/8. Not sure what the deal is. Any input is greatly appreciated.

[chopt50wgn]

I would unhook the fuel line to the carb. Put it in a bucket and have someone turn the car over. Watch to see how much fuel is actually flowing. You may have a pump going south.

[Rusty Shackleford]

I'll give it a shot. However, the pump is new within the last year.

[greg g]

did you assure you have no vacuum leaks between the carb and minifold???

[Rusty Shackleford]

I did not and I'm not sure of how to check for vacuum leaks.

[K_Jordan]

My car was doing the same thing and it turned out to be my dwell was too low.

[suntennis]

Assuming all you worked on is what you mentioned, it sounds like a fuel starvation issue. If you replaced the gas cap with a new one that is not vented, that would cause the problem you describe. If the float level is set too low, that would also cause the problem.

[moose]

My car was doing the same thing and it turned out to be my dwell was too low.

A wise man once said "90% of fuel problems are electrical." Be sure everything in your ignition is good to start with, but vacuum leaks are a good place to start too.

[T120]

A while back you were troubleshooting a zero compression problem on a couple of cylinders - was that fixed ?

[Rusty Shackleford]

Ralph, zero compression issue was fixed. New head gasket installed. As far as a non vented gas cap goes, I used the same one I had prior to the new tank install. This cap is no vented but the new tank has a vent line that I had to mount higher than the filler neck per the instructions. Not sure if I need a vented cap as well? I guess I'll try taking the cap off and starting it and see what happens.

[T120]

Hey Rusty,Glad to hear you fixed your compression problem.Also good suggestions here on resolving your possible carburetor problem.

[Don Coatney]

I did not and I'm not sure of how to check for vacuum leaks.

Use an unlit propane torch. With the engine running at idle open the torch valve and point the business end all around the intake manifold and carburetor base. If the engine RPM's increase you have a vacuum leak and you can pinpoint just where the leak is located. Dont forget to close the torch valve.

[Rusty Shackleford]

Well I tried the propane torch trick, no change in idle. I also removed the gas cap, no change. I checked the line from the pump to the carb and it seems to be flowing just fine. One thing I noticed is there is some fuel resting in the intake manifold. Is this normal, I have never noticed it before, although I wasn't really looking.

[greg g]

No. Stuck open needlee and seat or float leevel too high, or toomuch pumping while trying to start.