Postby Hasbeen » 29 Jul 2011 00:29
Ken this was a common problem in Oz in the early post war period, when everyone ran old prewar yank cars, with early 30s Dodges & Chevs everywhere. New cars were just not available.
No rubber fuel hoses available, they had copper pipe all the way from tank to carb. They would have a few coils, [like a coil spring] in the line to absorb movement, without work hardening, & cracking. Most of these had your symptoms, with fuel boiling in the pipes when stopped.
Most cars carried a canvas water bag, hung above or under the front bumper back then. We also carried an old towel. Before shutting down, dad would soak the towel in water, open the bonnet, [hood], & wrap the wet towel around the fuel pipe. This usually worked, & I'd suggest you try it on your car, if only to prove the symptoms.
Then some smart mechanic, [yes there are such things], thought about the problem. He realised you can only get a vapor lock if the vapour can't escape. He realised that if there was a constant rise, with no high points, all the way to the carb the vapor would have to rise to the carb, where it could pass through the float chamber needle valve & escape through the chamber breather.
Most of the systems had the pipe rise above the carb, then come down to the union. Once he eliminated any fall in the pipe the problem was solved. Word soon got round, & in our town nobody still had the problem a year later. Make sure you don't have a fall in your fuel pipe anywhere.
I'd also look for a flooding problem. After the lay off the needles may have become sticky with varnish from evaporated fuel, & not be shutting properly. I've had quite bad flooding stalling the thing, unless the revs were kept up, in the past.
The same thing can happen to the valves in the pump, depending on what it is. If the check valve is sticking open some times it can just work the fuel backwards & forwards, with little getting pumped.
Hasbeen
