Triumph Repair: Vapor Lock, fuel pressure gauge, electric fuel pump

Question
I have a 1970 Spitfire MKIII that has what I think is vapor lock. It runs extremely well, idles well, until it gets hot. Then, it has all indications of starving for gas and, if I don't feather the gas pedal, it will stall, then take an unusually long time to re-start. It has a single carb. I'm thinking of installing an electric fuel pump, or, a heat sink between the carb and manifold. Have you heard of this? If so, what do you suggest as a cure?
thanks Howard,
Bob

Answer
Hi Bob,
A vapor lock could be the problem but so could a dozen other things so you need to run a few tests.
First put a "T" in the fuel line between the fuel pump and the carb. and run a long hose to a fuel pressure gauge and run it out from under the hood and place it under a wiper blade so you can monitor fuel pressure when the engine is hot and running. Make sure the hose is clear of anything that will pinch it or cut it. Vapor lock (boiling gas) is of no problem between the pump and the carb but boiling gas is a large problem on the fuel line from the tank to the pump. When a fuel is drawn from a tank it lowers the boiling point of the fuel and if the pump receives this vaporized fuel it stops pushing fuel to the carb. When your engine starts to stumble and run bad, read the gauge. If the gauge reads lower than 1 1/2 to 2 lbs. then you either have a failing pump, obstruction in a fuel line or a vapor lock at the inlet side of the pump. It is true that an electric pump placed in the line close to the tank is much better design, be carefull about fuel pressure. If you have a mechanical pump like you have that puts out 3 PSI and you add an electric pump in the back that puts out 3 PSI you will have 6 PSI at the carb. If you put one in the rear, besure to bypass the mechanical pump on the engine and check the pressure at the carb.
Let me know.
Howard