Could someone describe the symptoms of vapor lock? My '57 BN4 has had a
persistent problem of sputtering when under load. Idles fine, revs fine, but
when given the gas to go up a hill or something, it'll run extremely rough.
When I say rough, I don't mean rough like when one cylinder is not firing,
it's more like a very rapid sputtering.
The timing's correct, the mixture's correct (per lifting the piston in SU
method & plug color), valve clearance is fine, no vacuum leaks that I can
find, & I've replaced the distributor cap, ignition wires, coil, plugs,
points, rotor, & condenser. I'm out of ideas. Could it be a vacuum advance
problem or does it sound like fuel?
The vehicle is 100% stock other than a spin on oil filter, so it has the
original "heat shield" (piece of metal) between carbs and exhaust manifold &
has fuel pump located above exhaust pipe.
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