~~I took the boat to the lake yesterday and pushed in the primer button/key when experiencing the decal chatter to see if that would help the problem. It made no difference at all therefore eliminating the possible decal detonation possibility. So it seems I have another problem which a few guys from another forum diagnosed right from the beginning. With these 60* 150/175 they have very little clearance between the bottom of the piston skirt and the block at bdc. When the pistons start to wear they will **** in the cylinder and the bottom of the skirt will start to tap the block because of tight clearance. Apparently this is common with these motors. When guys who know of this problem rebuild these they clearance the pistons by grinding a slight 45* on the piston skirts, no more problem. Unfortunate OMC didn't figure this out. Anyway, no telling how long the motor will last but I'm just gonna run it over the summer and hope for the best. Maybe sell it in the fall.
Thanks for everybody's help and input!
Thanks for everybody's help and input!