Ok. The clunk moves freely and does not hang up. The tank is a little lower then what they say it should be but It sounds like that shoudn't matter. This plane ran fine with a 46la in it and now with this 46ax it keeps deadsticking. I 'm going to run a tank of feul with it on the ground and see if it still dies. This engine has started and ran fine out of the box till it gets in the air and runs about 1/2 to 3/4 of the tank out and then dead.