Posted by David Sherman on Saturday, February 25, 2006 at 11:06AM :
In Reply to: 1948 flathead 6 problems. Help! posted by mark on Saturday, February 25, 2006 at 10:47AM :
I have not had a vapor lock problem, but if the heat riser is stuck in the "winter" position, it could definitely overheat the carb in hot weather. If the heat riser is stuck, or you're not sure if the flapper has broken off the shaft, the only way to fix it for sure is to pull and separate the manifolds. You can also check fuel line routing to see that nobody moved the line too close to the manifold.
You can test for crud in the fuel line by running a known-clean fuel hose from the fuel pump inlet to a jerry can strapped to the running board to see if that fixes the problem. Dirty fuel tanks or rotten fuel lines can be maddening because the crud sometimes clogs the line and sometimes gets out of the way. In my limited experience, the stock mechanical fuel pump is fine, and in general, adding an electric fuel pump to a vehicle that didn't have one originally is a waste of time and money that won't really fix the problem.