[Player]

When I go to start when it's cold it fires right up without much effort at all. Once its been driven (only ever driven it short distances, so far) it doesn't want to start. I've found I have to press the gas pedal to the floor in order to get it to start. Any thoughts on what's going on here?

It's a 351W that has had the carb rebuilt over the winter. Fuel pump, filter, and all other external normal maintenance items have been replaced.

Thanks!

[tripleblack]

Sounds like vapor lock, first blush.

If the symptoms include the engine turning over slowly and the starter straining, it might be a dying starter (they will react this way to heat).

[Player]

Thanks for the feedback! The starter seems to turn over just fine...normal speed. Just won't fire until I press the accelerator to the floor.

[blea9082]

Vapor-lock is most likely culprit. Are you driving the car enough for it to get hot? Oxygenated fuels are notorious for being prone to this. When the car sits after shutting off, the fuel in the carburetor "boils" leaving you with vapor instead of liquid in the carb. This will make the car hard to start, and require extra cranking on the starter until enough cool liquid gas has reached the carb. The best fix is to put an insulating spacer between the intake and the carb, and wrap the fuel lines in the engine bay with heat insulation.

[Player]

I haven't run to normal operating temperature...will try that soon.

If vapor-lock is my problem, though. Any suggestions for an insulating spacer for an Autolite 2100 and for good heat insulation for the lines?

[silver69]

I vote for float level too high. I think that you are having fuel bleed into the intake causing an over rich condition and when you floor it it opens the butterflies to allow enough air to get combustion. easy to check - look at your plugs closest to the carb for wet/carbon buildup
Joe
Double check to make sure the choke pulloff is adjusted properly - choke migtht be sticking

[Player]

Joe, so if the float level is a little too high then that would happen after driving it, but not after sitting for a more lengthy period of time?

I'll double check the choke, but I'm pretty sure it's good. Although the car is starting very nicely now that it's warmer out...it was much more difficult in the cold.

[Player]

Alright, I pulled a plug and it looks good (back right plug, don't recall which number that is...8 maybe).

I do have another symptom that may be related. When I'm driving and I step on the gas, there's a slight hesitation before it takes off. If the engine is cool (just beginning trip) and I don't give it enough gas, it will die on me. Once I've been driving it doesn't die, but does hesitate momentarily EVERY time I press the accelerator.

Does that help at all to pinpoint what the problem may be? Is it still a carb issue? And if so, what? Still finding my way around the art of carb tuning.

[tripleblack]

Originally Posted by Player

I haven't run to normal operating temperature...will try that soon.

If vapor-lock is my problem, though. Any suggestions for an insulating spacer for an Autolite 2100 and for good heat insulation for the lines?

If the car isn't even getting to normal operating temp, its unlikely to be vapor lock.

More likely the culprit is the carb, as silver69 said. If the car has been sitting up for a long time, though, adjustments won't fix the problem(s). The float may be sticking, and all the moving parts are suspect. You also may well have congealed crud in the jets.

My experience has been that just running carb cleaner through won't do the job...

[Player]

The carb was rebuilt over the winter.

Any input on my the new symptom?

[Player]

Anyone have any insights on this?