Gas draining back to tank when truck sets.?

Question

seems that when my truck sets the gas drains back to tank from the carburator. If i take the fuel line loose betwwen the fuel pump and the carb there is no gas in the line after it has been setting a bit. Is this caused be a needle or such not shutting in the carb or the fuel pump letting the gas leak back? It runs good when the truck is running just the hard starting that is a problem.

Answer 1

there should be enough gas in the carburator to start the engine without the pump working at all.

lack of fuel in the line points to a fuel pump that lets it drain back to the tank,

the float valve will only close if there is fuel in the carburator enough to close the valve.

I would check the fuel pump and also check if the carburator is leaking gas out when it sits.

Answer 2

Gasoline in carburetors cannot drain back.  There's no reason to build a carburetor where it could, so they don't.  It's evaporating, or leaking out the bottom of the carb.  That's common.

The gas in the fuel line may be draining back through the circulation line, if you've got one.  The fuel pump reciprocates, so obviously it has check valves, but it also sometimes has a recirc line that is used for pressure control.  It could leak either direction.

Answer 3

There's no problem. All carburated vehicles will do this. Just pump the gas several times before you turn the key.  

Answer 4

What is the year make and model please!

You can find repair info here!

http://www.autozone.com/shopping/repairG...