I have a 1992 Evinrude Tracker 40 hp. Pops out of gear when under load. I have tried adjusting all shift linkages over the last couple years. Have been able to manipulate into a position so it pops out only a little in forward but now it is a real issue. When putting in forward and at over 2,000 rpm it continually pops in and out of gear. Thoughts? Clutch dogs? Any ideas? How hard to replace.