I ask about trouble with my plane slowing down on hard turns, about a hour ago. It dois this after about two minutes of flight. I was told to remove the tank and check and run new fuel lines.

When I turn the tank side ways and upside down where should the clunk be? Like does it need to go to the front when upside down. Mine goes back and forth but thats it. It seems too redgeded to bend like that. I could see it being out of the fuel on hard turns or flying down .

Can some one explane the movement of the clunk in the fuil tank, and proper set up with it?

Thanks Tom

Clunk orients to the REAR of the plane and should be free to move side to side and up/down.

Conventional venting will lean out somewhat as fuel level goes down. You may need to go a tad richer on the ground setting since the motor will unload in the air going leaner. Additional leanness from conventional venting fuel use can make you over lean.

So my fuel line in the tank does not go up and down. just back and forth. I have it out am holding it up to the light to see what the clunk is doing.
Could the melal tube that gois into the tank be to long to alow the fuel tube to bend. mine is about 1x2 inch long inside? This is a 9 oz tank on a tower trainer .40 motor.
I understand about the motor leaning out in flight.

Thanks Tom

Tom,

Cutaway is right about the clunk staying at the rear of the tank. If it moves towards the front then that would be part of the problem. Add some stiff tubing to the line between the clunk and the nipple it attaches to so that it does not bend and come to the front of the tank. However, make sure it still moves all around the rear of the tank but that it does not touch the rear of the tank.

you want about 1/4 of an inch clearance when you hold the tank with the clunk hanging to the rear.