how tight on the prop nut on a 1968 johnson 20hp?

[kawaboy-zx11]

i am spinning props left and right, without ever hitting anything! i am wondering if my prop nut needs to be tighter, i was thinking that maybe the prop nut needs to be really tight against the the pin to compress the rubber in the hub so it wont slip? i mean i recently got a new (never been in water) prop and probably only have less than 20 minutes run time on it and its slipping already. here is a pic of the kind of hub i have. does anyone have access to a manual that tells what to torque the prop nut to on a the 1968 johnson 20hp? Thanks, Dennis

 

[AlTn]

well, tight enough to get the carter key through the prop nut and prop shaft

 

[kawaboy-zx11]

here is the working link to picture. http://oi61.tinypic.com/rv8tqs.jpg

 

[AlTn]

with the prop nut installed correctly, do you have any play between the prop and nut...if so..how much?

 

[ERock82]

Sometimes a new prop nut will do the trick. Happened to me.

 

[racerone]

Snug is all that is needed on these !!---And I do not believe that tightening more than that will help keep the rubber from slipping.

 

[F_R]

I agree with racerone. Tight enough to take the rattle out is all it needs. Actually, tight as it will go without force, and still get the cotter pin in. Has nothing to do with spinning hubs. I believe I already told you how the hub is made.

 

[kawaboy-zx11]

well, i went fishing this evening (did great 8 nice bass) i tightened the nut and it did not spin the prop today, i am not surprised because it probably will tomorrow, seems like my prop has a mind of its own and just spins when it feels like it..lol

 

[F_R]

I would suspect it is cavitating, but you said you marked it and confirmed slippage (??)

 

[kawaboy-zx11]

I would suspect it is cavitating, but you said you marked it and confirmed slippage (??)

correct.

 

[kawaboy-zx11]

went out again last night, did fine on the way out started spinning on the way in, then i let off and got on it again and it did not slip even wide open. the prop on it is a 9x10, i see there is an option for a 9.25 x11 prop for my motor. looks like i am going to have to buy yet another prop, what differences would i notice with the 9.25x11 compared to the 9x10? Thanks