1970 thunderbolt 500 lower unit or prop hub?

[68C15]

I'll be the first to admit I know next to nothing about this motor. I bought it a month ago from the original owner. he used it for a total of 6 years and never had a problem. neither did I until today.
I made a partially aggressive hole shot and got up on plane (1969 Alumacraft tri-hull) running real nice. then all of a sudden it felt like it went into neutral, engine revved up and forward motion dropped. I coasted to a stop and tried reverse. that worked wonderful. I then tried forward again. it moved but if I gave it any amount of throttle to get above 5MPH it started to "slip" again. I slowly made my way back to the ramp (3 miles).
I got it home and started to check into it. with controls in reverse you cannot turn prop but in forward you can turn it one way and feel a "clunk-clunk" but turning the other way it has some resistance but does slip without any clunking. I removed the prop and noticed the rubber "hub?" is deteriorated. (this is thru hub exhaust)

my questions

1. is there some sort of one way clutch for forward only?
2. I take it for granted my hub is shot, is there a heavy duty hub available? the boat-motor came with an extra prop which also has a crumbly hub.

thanks for any and all help. my wife and I really love our 15' Jamaican and we finally catch some NICE sized perch and walleye

Oh, BTW. I know my 1965 Johnson 100HP has electric solenoids for shifting. how does my Mercury shift?

 

[Droll]

Re: 1970 thunderbolt 500 lower unit or prop hub?

my questions

1. is there some sort of one way clutch for forward only?

Yes, the clutch are of the ratching type, made that way in case of a sudden loss of engine power ( allowing the propeller to spin freely instead of looking up )

2. I take it for granted my hub is shot, is there a heavy duty hub available? the boat-motor came with an extra prop which also has a crumbly hub.

You can get all sort of hub type propeller now, you can even get some solid hub propellers ... but for you engine I would assume any new propeller would do the job

Oh, BTW. I know my 1965 Johnson 100HP has electric solenoids for shifting. how does my Mercury shift?

Weren't any 1965 100 hp engines from Johnson that year. biggest were the 90hp .. first 100 came in 1966 ...
But anyway... the Johnson and Merc are 2 different animals

Mercury used a totally mechanical shift ( a cam on the end of the shift rod moves a push rod that will move the shift dog ( clutch ) between reverse/neutral/forward .

Johnson ( 90/100hp 1964 > 196? ) used a shift spring on each gear ( NO clutch), when shifting you just send a current to a electro magnet that magnetize the correct shift spring...
With a bad battery and/or a faulty electric wiring you would be stuck out on the water without any propulsion...


Arne Kjetil