shear pin to slip clutch

[laxcker]

I have a 1977 Johnson 25hp. The lower unit is a shear pin type. Is there anyway to put a slip clutch lower unit on it ?

 

[F_R]

It already has one, built into the propeller. Are you using the correct pin? It is a part number 307949 DRIVE pin, made of stainless steel. But I think your real question is can you convert it to a splined prop, with no drive pin. I think it may be possible, but I'd have to do some research on that. Meanwhile, my question is it worth it? You will be spending a few bucks.

 

[F_R]

OK, to the best of my knowledge, you could change the prop shaft and prop to the splined version. A 763589 (9x10) or a 763584 (9-1/4x11) prop lists at $148.50. The 344231 prop shaft is NLA (no longer available from BRP). Last price was $275.98. You also need some seals and oil etc, + labor.

 

[racerone]

Agree with above.---You can install a newer splined propshaft and the splined drive prop.--------The " slip clutch " design may be fooling you and many others.---Generally those splined drives will ruin your prop when you hit something and props are not cheap.-----If changing a pin is a problem for you and buying new props ( money ) is not a problem than the slipclutch is the way to go.

 

[F_R]

Actually, they both have the same "slip clutch" in the prop. The only difference is the way it is driven, pin or spline. You might shear the stainless drive pin if you mortally clobber something, whereas you can't shear the spline. Either way, expect prop damage. The clutch is the last line of defense before wringing off the drive shaft.

 

[gm280]

Not knowing the real reason you are looking to change to a slip clutch setup, if it is because you are constantly shearing pins, then buy a factory replacement type prop pin and see if that shears as easily. Some times shear pins are replaced with weaker material like brass pins and they will not hold up to the hits like stainless steel pins will... JMHO because I don't know your setup or reasons to want to swap...