Spitfire Won't suck gas when hot.

[simpzimmer]

Thanks for all the help through the years. Recently, my Spit has quit on me a few times. Will start beautifully cold every time. I'll drive for a while, then stop and sit for an hour or so. When I start back up, it'll run for a few minutes, then stop completely. Assume it's burning what gas is in or near carb. When I remove the fuel hose at carb, there is no gas coming out when I turn over the engine. I can feel fumes coming out, but no liquid. The only way I've fixed is to siphon it up, resulting in a mouthful of gas, replace line and start. I've replaced the upper fuel lines thinking there might be a pinhole or something keeping it from pumping all the way to carb. Diaphram looks good. Strange that it only happens when it's hot, then cooled. Grabbing at straws, starting with easiest, I figure I'll replace fuel filter, pump, then tank??? Thought maybe carb had an issue inside??? Curious if anyone has any ideas??? Thanks, Greg

 

[poolboy]

If the engine sputters a bit before it dies, you might try opening the gas cap and see if it comes back to life.
If it does, maybe we can deal with the situation without having to replace a bunch of parts..

 

[simpzimmer]

So it might be vapor locking? Makes sense. Aggravating because it only does it when it's hot. Never when I'm at home in the garage.

 

[TR3TR6]

The above are good replies. You might also check how close the fuel line is running to the engine block. I had a similar problem when I had my Spit. After changing a number of things out, it turned out the fuel tank was plugging up the fuel line with particles from inside the tank. Cleaning out the tank cured the problem. You might disconnect the fuel line before it gets to the pump and see if the fuel comes out.

 

[TomMull]

Classic vapor lock symptoms. However, the cure is sometimes difficult. If everything is working properly, it shouldn't vapor lock. Most of the suggestions above can contribute to, if not cause the problem. I try to eliminate as many potential problems as possible before putting in a new pump but ultimately, the new pump usually fixes it. Even though your diaphragm looks good, you can't tell how well the check valves are working by looking. Finally, even though you see no gas at the carb, check the spark for yucks. I've been caught more than once chasing what I was sure was a fuel problem that turned out to be electrical.
Tom

 

[dklawson]

Also, if your fuel pump has a removable top cover (like some of the early ones) remove the cover and inspect the gasket between the lid and the pump body. If the gasket fails to seal (due to expansion of the pump parts) then the pump will not draw fuel from the tank.

 

[simpzimmer]

Thanks, you guys are great. Sounds like cleaning tank would be worth the effort. Spent some time on it yesterday. My fuel line was sitting on the block, probably not the best thing. Also, when I turned it over, some gunk came out of fuel line. Will check pump seal as well and twist-tie line off the block.

 

[tdskip]

Also worth asking if you have a heat shield installed - they do work.