GTMUSTANGCS

I have a supertigre 40. The fuel is not flowing from the tank to the carb when i put the starter on it. Air bubbles are not moving toward the carb. I have looked at everything and cannot figure it out. Any suggestions? maybe soak the carb in cleaner? Thanks

larrysogla

When you choke the carburetor mouth with your finger and then flip the propeller......does the suction effect draw fuel???? can you see the fuel moving in the clear fuel line???? does your carburetor become wet with fuel???? If the answer is YES, then the fuel line clunk and the fuel line are OK (if there is a small air leak in the fuel line or the carburetor or the engine crankcase, the fuel will still be drawn when you choke the carburetor throat)..........if the fuel is being drawn when you choke the carburetor mouth then the next thing to check is if the fuel hole in the carburetor spray bar is pointing downwards and is at the center of the carburetor throat. This can be visually checked when the carburetor is removed from the engine and then looking from the bottom of the carburetor the hole in the spray bar should be pointing directly to the bottom opening of the carburetor. Then if everything is OK, the engine has to be spun with a starter to see if the fuel is being drawn. 'Nuff said.

Kaos Rulz

If you still have no luck after trying everythinig Larry suggested, double check the lines to ensure they are not crossed. You might have the pressure line (normally going to the muffler) attached to the carb.

SeamusG

Uh, dumb question (and apologies) - is the high speed needle open? I've gone to the field and my HS needle has been closed and I forgot to back it open. No, I don't normally do this but just in case ...

A simple test to see if the clunk is free-n-clear is to hold your plane nose up and waggle it around. You will hear the clunk banging of the sides of the tank if it's clear. No banging? Then the pickup line w/ clunk may well be bent over on itself and the clunk is stuck.

Another way to prime your engine is to put your finger over the muffler outlet. When you turn the prop manually there should be sufficient pressure in the muffler to apply pressure out the nipple and into the tank. I do this until fuel is visible in the carb throat or it gets wet and drips.

Either Larry's or this approach will allow you to hold the plane still while the prop is turned.

Oh yea, to test your tank's ability to hold pressure, clamp the fuel line to the engine tightly, blow air into the tank using the pressure line from the muffler and pinch it off. Hold for 15 seconds. Release the muffler pressure line - you should hear a release of pressure. No sound? A leak. Btw, if you release the fuel line to the carb - do yourself a favor - don't point the line towards your face "to hear better". Just sayin' ...