Where can I get a needle shutoff valve for glo fuel line.
Why do you need one?
For heli's and pylon planes we use a small plastic clip that will pinch off the fuel. Reason is not for shutting of the fuel, but to ensure not flooding the motor when filling it up.
The more valves and connections you have in your fuel line, the more chances for air leaks. Try to keep you connections to a minimum.
On a sport plane, if you need to turn the motor off, you should have the throttle set up, so when you are at low throttle and low trim the barrel is completely closed so there is no air. The motor will die.
If you want to ensure there is no fuel left in the system for storage, empty the tank, then put on you battery and spin it over with an electric starter. It may pop and die very fast and no you have just burn off any fuel in the line. If you don't have an electric started, its a real pain.
Remember to put a couple of drops of afterrun oil after you have run it dry.