My poulan 2150 will not start. OK here goes with things I have done. I have replaced 3 coils and all the fuel lines. Rebuilt carb. Replaced ground and kill wires. I have tried air gap at 25 and 15. Compression checks at 120psi. This unit will not fire with starting fluid. I have replaced 3 spark plugs and set gap at 25. I have watched flywheel and air gap clearance for possible bent crankshaft. I have an identical 2150 that I have rebuilt and it runs fine. I am about to start swapping parts from it. Is there a reed valve that I am overlooking? Anyone up for solving this problem?