Troubleshooting 1976 Mercury 20HP Outboard: Gear Engagement Issue

Question
My old Merc runs great, but when I take it to full throttle it acts like it comes out of gear and revs hard.  Backing off the throttle engages the prop again.  Is this economically fixable?

Answer
Hi Joe...Thanks for selecting the undersigned to reply to your question.

Considering the engine is 31 yrs. old, I doubt it would be economical to repair, besides, where would you likely get the parts. I don't think Mercury still carries parts that old, but it's worth going online and inquiring.

Safe Boating
Ron