near empty fuel filter

[71 SPORT]

Is it normal for my fuel filter to be near empty all the time ? Even on start up (no heat) , if i turn the key to the on position it will fill up almost all the way but while running it nearly empties and bubbles up some fuel occasionally. I have a carter electric pump and i just redone my fuel lines with metal lines on the outside of the frame rails , thinking possibly a pin hole in the rubber hose on the sucking side but still nearly empties out. It stays around 6 psi and doesn't stall . its not the tank i installed a new 23 gal. and the filter before the pump fills up completely and stays that way. Is it possible the selector valve is not sealing off completely from the aux tank (i rarely use the aux tank and is usually empty) ? I have one of those glass filters to see this happening .

 

[broncnaz]

I think its fairly normal. My theory on this is a little air gets trapped in the filter due to the needle valve in the carb closing and fuel level in the filter covering the outlet so it wont fill up all the way. Shouldnt be a issue

 

[kayakersteve]

As long as it runs fine...

Should be OK. If hesitation, then may need to explore.

 

[Explorer]

While that is pretty much normal, it could be getting some air from the selector switch. They do leak from the seal like a kitchen faucet when they get some age on them.

 

[Muddypony]

Mine is always like that. Never a problem.

 

[blubberfet]

There is always some air in my filter. It runs around 1/2 to 3/4 full of fuel when running. When it sits for a day or two it will be empty. I can't find a leak anywhere and it starts right up. I have a mechanical pump.

 

[markperry]

If you are running rubber lines anywhere, you might check the clamps too see if they are tight enough, you could be getting air in through them also. The rubber line will collapse when they get older, need too check that also!