51 Fleetleader flathead 6 - engine stalling when hot and under load

51Poncho · Member

51 Fleetleader flathead 6 - engine stalling when hot and under load

Canadian Poncho · A Poncho Legend!

Sounds like perhaps you are getting vapor lock. Some folks convert to an electric fuel pump and this seems to solve the problem. You could try insulating the fuel line.

Fitz · Guru

Vapor lock is a good start to do your research, but it's not happen often on those 6.

If you lost your engine under load I suspect a lack of gas. You need a good level of gas inside your carb and good poppet valve in the gas pump, like a good diaphragm. Your carb must be clean and free of everything outside gas.

You may experience a vaccuum leak, also, your 51 must have the 1 barrel carburator, so a sleeve under the carb is press in the intake and over the year, the exhaust gas running around when the heat riser valve is working (or was..) corrode the sleeve by the outside of it and make hole. The hole can be as big as 3/8" dia. So your engine swallow exhaust gas a lot and drop the vaccuum.

You may be experience a small of everything above also.

Good luck.

PS: your Pontiac look good!

Fitz.

Harley61 · Veteran Member

I had problems with mine and is was the accelerator pump in the carb, replaced the plunger leather and all is well

Beaumont4008 · Uber Guru

Wonder if he ever solved the problem. 51poncho did you ever get it running good.

51Poncho · Member

I'm not sure if I have fixed the problem. Last fall I had the gas tank purged and lined. To keep it running cool, I pulled the thermostat and have the heat on full. As long as it runs cool, it seems to be good. I don't like driving it when the days are hot. Harley61-thanks for the tip on the plunger leather in the carb. Can you tell me the connection between the plunger leather and the stalling when its hot? Fuel was still getting to the carb after it stalled.

51Poncho · Member

Harley61....What is the reason for the stalling if it was the plunger leather in the carb? I disconnected the fuel line when it stalled and it was getting plenty of fuel. Was the engine stalling out because it was being flooded?

Harley61 · Veteran Member

What was happening to mine was when it got hot you would step on the gas and it would sputter and die because the engine was starved for fuel when the throttle was all the way open, I was still getting gas to the carb just not enough to the engine under load.