1990 Force 50 hp drive shaft question

[ja15435]

Quick question, what supports the weight of the drive shaft?

I pulled the lower to replace an impeller and found the impeller pin ground down to about a 1/16" dia. and the back plate worn from the contact.

I'm assuming that's not supposed to happen, and the drive shaft wants to sit lower than it should. Meaning and issue with the pinion gear/drive gears or the spline.

Or is the drive shaft weight carried by the impeller pin and backplate?

 

[Frank Acampora]

Re: 1990 Force 50 hp drive shaft question

Nothing supports the weight or any thrust of the drive shaft. It is a splined fit in the pinion and can be pulled completely out of the lower unit if the water pump is removed.

Now, that said, I have never had the problem. When I install a new impeller, I always slide the impeller down the shaft and over the drive pin. Since you appear to be having a problem, SOME of the impellers do not have a full length groove for the drive pin. IF you find one like this and if you slide it over the shaft, then pull up on the shaft and insert the pin, the pin and impeller will keep the shaft from entering the lower unit too far.

 

[catfishcarl99]

Re: 1990 Force 50 hp drive shaft question

yep franks right on. ive had mine apart several times. the drive shaft just slips into the top with splines and into a lower gear with splines. it all just rides like that. might be time for a new wear plate.

 

[Nordin]

Re: 1990 Force 50 hp drive shaft question

As Franks says the impeller should be slided over the shaft from top. The shafts own weight is carried in the piniongear
I have worked with severals of Chrysler/Force 35-55Hp (similar to yours) and have never seen what you explain.
Have in mined that there is a force upwards the drivshaft when the drivshaft and propshaft turns under load.

 

[ja15435]

Re: 1990 Force 50 hp drive shaft question

Thanks ,for the info guys. Just didn't want to overlook a potential problem.

Completely overlooked what would happen with the pinion under load. Maybe 20 years of idling just got the better of it.

I guess I'll pull it after a few seasons and see where I am. In the mean time find a splined bushing I can grind down to act as a spacer if it's still a problem.