1985 mercury 150hp black max driveshaft

[tommytwogunnz]

I have a 1985 mercury 150hp black max with a broken driveshaft. It does have the preload pin on the top. I have found another lower unit with the same number of splines on both the driveshaft and prop shaft. The gear ratio is also the same 2:1. However, the other lower unit does not have the pin on top. So obviously my question is will it work properly if I mount it up? What is the difference between the two (other than the obvious fact of the preload pin)?

 

[Chris1956]

The preload pin is used with certain kinds of bearings that require downward spring pressure to operate. As long as you use the correct driveshaft for the kind of bearing, the Gearcase will bolt up and operate properly. So, you can't install the non preload pin driveshaft into your current gearcase.