Have Classic Car Questions? Ask an Expert.
It sounds like you may have a blown head gasket.
Does the engine misfire while just setting there in park idling or while reving it up in park?
The accelerator pump is only for when you punch the throttle, it squirts gas down into the carb bore, for acceleration, hence the name. It has nothing to do with deceleration, and usually you only notice that it is bad when punching the gas pedal you get a hesitation.
So explain to me again exactly what the symptoms are.
Does this have a vacuum advance in the distributor cause hesitation can also be caused when that goes bad.
How is the base idle? Does the engine idle ok? Is the choke fully open after the engine is warm?
The stalling while foot off the gas and turning could be due to a base idle that is too low.
Does the choke fully open after the engine is warmed up?
Make sure you are not dripping gasoline down the throttle bores. Grab a flashlight and a mirror, so it don't backfire in your face and look right down the throttle bores while the engine is idling and look to see if any gas is dripping onto either or both front throttle plates.
Ok, let's start with the basics, what is the base timing set at, what is the base idle rpm, what is the amount of intake manifold vacuum at idle?
I suppose you shouldn't have to answer the base idle question since the other carb was the same but it would be ok to answer anyhow, just so I know.
When it spits out the carb, you said it's gasoline and smoke. Is it like a white mist? If so, that indicates a possible timing chain problem and either it's very loose or it is loose worn enough that it jumped but I doubt if it jumped because it would run poorly.
A good way to check if it's worn is to hook up a timing light, rev up the engine to when the timing in the distributor stops advancing, probably around 2,000 rpm, now rev it up an additional 1,000 rpm, so to 3,000 pm and then back and forth between 2,000 and 3,000 rpm and watch that timing mark. This throws the slack in the timing chain from one side to the other and if the timing mark moves more than 1/2" like this this most likely indicates that the timing chain is worn out.