[mwbaughan]

Well it is official, I pulled the lower unit and removed the water pump assembly and the shaft spins freely when the gear case is in gear.
Looks like a special tool may be needed to proceed further (has off ->). Anyone have a x-long drive shaft (measures 28 3/16" tip to housing. Also, it appears that the little bolt on top of the shaft must have been sheared off (stuck up there still?). Any help and advise is appreciated.

Thanks...............Mark

[CharlieB]

Little bolt?

The top of the vertical shaft is splined, no bolt.

That it spines freely while shifted into gears is only a sign that something is wrong.

I wouldn't order parts until you get the gearcase apart and have the damaged pieces in your hands.

[mwbaughan]

Some have the little 1/4" alignment threaded bolt on top of the splined shaft.
This one had it, but it was sheared off when I dropped the unit.

Don't have the tools to disassemble the unit.

[cannonford57]

no bolt ,just a spring loaded preload pin on top

[Faztbullet]

The part number you need is 45-41509A2. It is NLA from Mercury so you will have to find a dealer that may have it in stock or a used one. That is a preload style unit and if you find a new one price is around $600.00up and Marinepowerservice.com say they have it in stock for $699.00. If it where me I would look for the later style unit and install. The newer units are the 1986-2004.