The fuel boiling out of the carb after shutdown makes for hard restart

[hawkaleuge]

The fuel boiling out of the carb after shutdown makes for hard restart, anybody actually fixed this? I installed a 1 inch plastic carb spacer, no luck, fuel line insulation, no luck Thanks in advance Ed L.

[Rickf1985]

OK, I see you here in the Dodge section. Dodge did also use a version of the EFE valve on the exhaust manifold on certain years. I am not as knowledgeable on the years used but look for a vacuum line leading to a butterfly valve on one of the exhaust manifolds right where it meets the pipe. When the engine is started cold this should close and then open as the engine warms up. Follow the line up and it will go to a thermo-valve. You can pull the vacuum line off when it is warmed up and the valve should close. If no movement you have to determine if it is open or closed and then get it open.

[cosmic]

2 circular gaskets on the bottom of the carb. (carter thermo quad)  dry out and leak. causing the engine to run rich. where you see the gas coming up is where those o rings are. if you take the jet caps off be sure to use miller Stevenson 905 epoxy. nothing else will hold up against ethanol fuel (because of the alcohol) trust me I did the rebuild and found out the hard way 3 times. only lasted 2-3 weeks each time. mine was doing the same thing with the fuel and the restart. now it works great... I bet you have black soot at the end of your tail pipe..

maybe mark can find the post because I tried and cant.  good luck.

[DaveVA78Chieftain]

I am not real familure with the 413 however I do know the original carburetor was a Holley 4150C.  TQ was only installed on the 440-3.
On 413, Dodge did route cooling water through the intake manifold to heat the carb.

Dave

[cosmic]

sorry I missed the 413.. D:oH!

[hawkaleuge]

I disconnected the water heater line that goes through the intake manifold and plugged it.  That didn't help either.  I will be rerouting the fuel lines next as the current routing follows the exhaust pipe down the frame rail.  The gas nowadays boils if you look at and it's worse in the mountains at 11,600 feet on passes.  I'll do my fixes now and see if it did the job when it gets hot again.


Thanks for you input
Ed L.

[Rickf1985]

What carburetor are you running?

[legomybago]

Install an electric fuel pump in that baby. Problem solved

[Rickf1985]

An electric pump will not stop it from boiling in the carb when stopped, neither will relocating the fuel line. Both of those things will stop vapor lock which is fuel boiling in the lines though.

[MotorPro]

What makes you thing the gas is boiling out? In 40 years of engine building and racing I have never seen gas in a carb boil away. It does often leak out into the engine.Making it hard to start. Rebuild or replace the carb.

[hawkaleuge]

I do have an electric fuel pump and it did solve the vapor lock problem on mountain gas and passes.  The carb is a holly 4150 vacuum secondaries a electric choke universal carb.  I replaced the float needle valves and adjusted the fuel level a bit lower than recommended.  On a short start up and and stop the butterfly valves remain dry,  A longer run that heats the engine up results in fuel wetting out the butterfly valves and and flooding the engine.  I thought it was from engine heat on the carb or the exhaust manifold getting hot enough on the fuel line to blow gasoline through the float valves.  I have tried the spacer,  now I will reroute the fuel lines away from the heat.
Ed L.

[hawkaleuge]

And the winner is Motor Pro for correctly identifying the problem.  Thanks
I rerouted the fuel lines and still got the fuel wetting on the carb plates.
I then pulled the bowl level plugs and no fuel came out, also loosened the float needle caps and they had pressure no leak down. 


The fix was to replace the gasket between the throttle body and the venturi body of the carb - the leaking stopped.  full testing will be needed at hot temps to confirm.


Ed L.

[MotorPro]

Glad I could help