I had a problem I always though might be vapor lock or at least fuel
that was too hot.
After driving the car until it was fully warmed up, if I stopped for a
few minutes at a store it would then be hard to start, not want to idle
properly, and run rough for a few miles. This usually went away after
what I estimated to be about the same amount of time that it would take
to use up the gas in the floats and/or fuel line.
The solution I came up with was to "insulate" the fuel line. I use that
term loosely because I think I isolated the fuel line as much as
insulated it. I used some black split flexible polypropylene tubing
that is intended to go around wire looms. It was what I had on hand
that fit the bill when I decided to try something to insulate the fuel
line but it was quick and cheap. It made an immediate difference.
I don't have the symptoms I described above with hot start, idle, or
rough running, anymore so I'm satisfied that I may have solved the
problem without knowing for sure what it was. Now granted we haven't
had the 90+ degree ambient temperatures this fall like we get in summer,
but it worked on 80+ degree days so I'm just gonna leave it there and
see how it does next summer.
The size flex tubing I had was 3/8" which I would guess is about double
the diameter of the copper fuel line. It fits on loosely but doesn't
sag. I put it every where I could on the fuel line from the fuel pump
to the carbs. It's outside diameter matches the diameter of those small
pieces of black rubber fuel line so it makes the whole line look better
IMHO. Always thought that copper tubing looked out of place anyhow.
Don't forget the fuel line under the carbs which is actually the closest
portion to the manifolds and probably where most of the heat problem
is. I think most of that flex tubing is heat resistant to 200 degrees
so it shouldn't have a melt-down.
It's a cheap fix ($5) or at worst a cheap attempt at a fix even if it
doesn't work for you.
Good Luck
Bud
Winnie Olmer wrote:
>
> Could someone explain vapor lock in detail. What is happening to the fuel
> flow in the lines, carb and cylinders? What are the symptoms? Aside from the
> exhaust header heating things up, could hot weather cause it also?
>
> Thanks
> Winnie
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