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Well, I've got sick of the 360fe in my '72 f350 vaper locking every time I have to re-start it warm. It has the factory 2100 on it and factory style fuel pump. It does have a spacer under the carb. I've rebuilt the carb twice, and there's nothing wrong with it. Float is set perfect. Every time I shut it off it vaper locks, even on a 40 degree day. Its done it as long as I've had the truck. I've put 9000 miles on it now. Once it's running it runs perfect. Someone did a electric choke swap at some point. Could that be causing it?
How thick of a spacer? Normally a 1" thick phonolic spacer takes care of the problem. They also make insulating gaskets where you stack plates in between setting up multi layer insulation.
Just to be sure connect a volt meter to the BAT side of the coil and read the voltage while cranking the engine.
I know this sounds weird but make sure that there is 12 volts present while cranking when cold and hot.
How thick of a spacer? Normally a 1" thick phonolic spacer takes care of the problem. They also make insulating gaskets where you stack plates in between setting up multi layer insulation.
Just to be sure connect a volt meter to the BAT side of the coil and read the voltage while cranking the engine.
I know this sounds weird but make sure that there is 12 volts present while cranking when cold and hot.
The coil is good. The truck smells of fuel when you shut it off hot. Its a fuel problem I'm 99% sure.
For ambulances at the dealer Ford made us wrap the fuel lines with some asbestos cloth looking fiber wrap that was foil on the outside and used snaps
Came in lengths
Took about 10 feet per truck but it worked
The whole metal line the whole way
This was the pre fuel injection 460 Holley version of a F350 small ambulance
Alky in the fuel is a problem for carburetors and older fuel systems
It looked like this stuff, only with snaps about every 6 inches to secure the pieces I punched up 3/8 fuel line heat shield on Google, this is one of them that came up. It looks just like the Ford stuff without the snaps.
Every time you do a hot start is the engine flooded? What happens is the fuel in the line between the fuel pump and the carburetor needle boils, overcomes the pressure that the needle can control and floods the carburetor. The best solution is to make a way for the built up pressure to escape. One option if you have a fuel pump that you can take apart is to drill about a .010 hole from the pressure side to the suction side or figure out some other arraingement of fittings to make this work. The hole can be very tiny.
Here's how I set up a return fuel system on a 4412 for a circle track car where fuel purolation was a problem: In that application I just used a Dominator style bowl with two inlet feeds. The one on the one side that comes from the fuel pump is normal. The one on the drivers side has about a .015 orifice to allow fuel to circulate back to the tank. As soon as the engine is shut off fuel pressure goes to zero.
Modern fuels have a much lower boiling point than gas from when these trucks were built. Anything you can do to help lower the temperature of the fuel lines, pump and carb will help. I would start at the carb. If your spacer under the carb is the old heated style with water hose running to it, replace it with a phenolic spacer of about the same thickness. One inch works pretty well for me.
If that doesn't fix it, I would look at the line from the pump to the carb. If it is still a metal line, make sure it's not touching anything. You can wrap it with insulation or replace it with a rubber hose. I like using fuel injection rated hose. It's higher quality and is more resistant to the ethanol in the gas.
If you still have problems after these changes, it gets more complicated. Check to be sure the line from the tank isn't too close to the exhaust anywhere. The ultimate fix is to replace the fuel pump with one with a return line to the tank. Check Uncle Tony's Garage on YouTube for detailed explanations on how and why
Just to be sure connect a volt meter to the BAT side of the coil and read the voltage while cranking the engine.
I know this sounds weird but make sure that there is 12 volts present while cranking when cold and hot.
Definitely look at this also. I had the same problem on a 390. Would not restart hot after sitting around 5 minutes.
Was only getting 6 volts to the points during start instead of the 12. Corrected wiring, and it never had a hot no-start problem again. This was back in the full-service gas days. Every time I fueled at one gas station, the attendants had to push me off to get my car started.
Also, how much ethanol in your gas? High ethanol will cause boil off.
