25hp prop sahft compatibility

[drstump]

I have a 1977 Johnson 25hp - model 25r77h. This motor has a shear pin prop shaft. I have been told there are splined prop shafts from later model motors that will fit my motor. I have noticed that the 1978 version of my motor does have a spline shaft. I use this motor mostly in rock bottom rivers and would sure like to get rid of the shear pin.

Anybody have information on prop shafts that will fit gear case of my '77 25hp???

Thanks in advance!

 

[Mas]

Re: 25hp prop sahft compatibility

I do not know about the compatibility, but it seems that I would want the shear pin if you run in those conditions as described. Why are you wanting to change?

MAS

 

[drstump]

Re: 25hp prop sahft compatibility

You are motoring up stream, hit a boulder and shear the pin. You are now dead in the water and at the mercy of the current, while you try to remove the prop, replace the pin, all while everything, including you, are suspended above the water hanging out over the transom. Can be a little scary in some circumstances.

Props for spline shafts have a bushing that allows a little give, kind of a relief clutch, so that hitting an object can be better tolerated.

Best thing is to be careful and just not hit anything.