Are drive shafts interchangeable before 1992 and after 1993 for 9.9's / 15's

[909]

As I'm trying to convert a long shaft to a short shaft. If I recall they changed the splines at the top of the drive shaft at some point , but it would be good to confirm if they are interchangeable between generations since it's nearly impossible to find parts motors for the newest generation 2 strokes after 93, but plently of older generation 2 strokes prior to 92.

 

[Crosbyman]

have you considered just raising the transom 2 inches if feasable for you.
I did that several years ago for a Classic 50 mounted on an 18 inch transom.

Worked out great.

 

[909]

That's a great idea. And I would do that, except I have other motors that are all short as well that I still want to use.

After speaking with a few friends, they advised me that the splines changed from 4 to 8 once they switched over to 4 strokes.

In theory drive shafts from the 70's , and 80's would fit the ones from the 90's and 2000's . But because of the groove for the O ring , it creates weak point and the old style shaft will snap.

 

[rolmops]

It is not very hard to make the long shaft shorter. Just take it to a tool and die worker with a lathe and tell him how long you want it. It should not take very long.

 

[racerone]

The 84 and newer did not use the o-ring.

 

[909]

The 84 and newer did not use the o-ring.

Thank you ! I'd buy you a beer if I could .

 

[saltchuckmatt]

On the 6 to 8 HP series they changed the splines halfway through 91. Driveshaft from that era are hard to find. My prop shop buddy cut mine down and welded it and it worked out great.

Besides the drive shaft, the shift shaft is to long and you have to cut down the water pickup tube with a Dremel.
Everything needs to be accurate. Best thing to do is find a parts motor.

 

[racerone]

Have you seen any of those driveshafts snapped at the o-ring groove ?

 

[909]

It's going on a 94 with bigger displacement