Fuel line question

[Loosenuts]

1979 340 Trailfire....the fuel line from the tank to the pump will not fill up wth fuel. But the line from the pump to the carb does. Any idea as to why the line to the pump has air in it. You can see fuel trickle into the filter before the pump but it will not completely fill up.

Things I have done.
Replaced pump with a new Mikuni
All new fuel lines including the one in the tank
Clamps on all connections
Tried two different fuel filters

Is the filter in the tank suppose to have a check valve in it.....because the one I pulled out does not.

[JDT]

My bet is you either have an air leak on the gromet on the fuel tank or a crack on the plastic fitting on the tank.

[Loosenuts]

My bad....I didn't say I put in a new rubber bushing into the tank also. I was surprised that part is still available from JD. The tube that goes through the rubber bushing is aluminum I believe.

[JDT]

It must be sucking air from somewhere.

Maybe the line in the tank is not at the bottom?

[Danzig]

If a fuel filter fills up, it's showing restriction, a fuel,filter half full is what you want to see.

[Matt]

If a fuel filter fills up, it's showing restriction, a fuel,filter half full is what you want to see.

Yea, as long as the line from the pump to the carb is full, that's the important part.