1969 50 hp merc stuck in gear.

[littlelakeden]

hi guys i have a 1969 50 hp merc.the motor is stuck in gear .i thought it was seized but i can move the fly wheel a bit and and prop moves a bit when i move the flywheel.when i move the shifter linkage on the motor it slides easy and dosen't click into forward or reverse.can anyone help me with this problem.