1973 65 hp merc wont go

[scottyisback44]

Hey guys. I just bought a boat with a 65 hp mercury thunderbolt. Serial #3661873. I got it running today and put it in the water. It revs up but doesnt really move. I brought it home and noticed that the prop would spin by hand when it was in gear the opposite way. For example with the motor in reverse you could move the prop the opposite way (obviously by hand the motor wasnt running.) So I decuided to take the prop off. It wasnt very tight at all. There was no shear pin to be found nor did I see a spot for one to go. Once off there was a tar like grease covering the splined shaft. I put everything back together and tightened the nut down on the prop. Am I missing something?? Could this be prop related??

 

[steelespike]

Re: 1973 65 hp merc wont go

Most likely it has a splined shaft and no drive pin. It may have a spun hub.
Remove the prop draw a waterproof line across the hub and do a test run check the line to see if it is broken.
A prop shop can rehub it.If it seems cost effective.
The goo on the prop shaft may be from the spun hub or a lube use to keep the prop from getting seized on the shaft.