70's Mercury 20 hp Lower unit issues

[KingRichard2020]

Bought what I think is a 1973 Mercury 20hp outboard. Put it in the water for the first time, and it started up great. Shifted into reverse and forward just fine, although forward and reverse are backward because the lower unit was replaced at some point. Anyways, it would idle fine, start fine, the motor seemed to be all good, but when I went to rev up and take off, it just revved up but didn't go anywhere. I am not cavitating. The gears seem to be slipping in both forward and reverse. This leads me to believe that the lower drive shaft gear, or whatever you call it if it has a technical name, is stripped out: being the gear that connects to both the forward and reverse gears.

Am I going to have trouble trying to find parts for this motor? I've gotta think so given its age. Nothing on Facebook or craigslist right now for similar motors for parts.

Any advice on helping me identify what exact part I would need would be very helpful

I can do the work of replacing, ideal scenario for me would be to be able to find an eBay part, slap it in, and be on my way.

Really like how this motor runs, and don't really want to part it out or sell for parts, but will if it's a lost cause.

Thank you for any help on this

 

[flyingscott]

I would look at the prop hub before anything. When you shift into forward can you grab the prop shaft and turn it( motor must not be running for this test) .You have the correct lower on that motor. Mercury shifted backwards until around late 73 early 74.

 

[KingRichard2020]

Should I be able to/not be able to turn it a certain way?

 

[KingRichard2020]

I can turn it , and turn over the motor while doing so, but it seems like there is a bit of give before the shaft actually turns....

 

[KingRichard2020]

Took off prop, and the rubber bushing on the prop has been spinning inside the prop and got hot it looks like

 

[KingRichard2020]

Will I need a new prop, or can I replace just the rubber bushing? Basically am I able to take it out and press in a new one?

 

[flyingscott]

Took off prop, and the rubber bushing on the prop has been spinning inside the prop and got hot it looks like

Its common for those old props to start losing there hubs. The rubber is old plenty of replacement props out there for it.

 

[racerone]

Lots of used parts are available for these motors.-----Your location ?