Changed the water pump on my 1982 Mariner 50hp lower unit S/N 5965200, and I am having trouble getting the shift shaft right. My motor has a sloped cam on the shift shaft instead of the the sliding clutch shown in the manual. When you shift gears the female spline in the leg moves CCW and doesn't move CW. Also, the shift shaft spline on the lower unit, moves about 30? CW to match as if it is spring loaded. It doesn't move CCW at all. So I can't move the shift shaft on the lower unit. I tried to using pliers, but I didn't want to mess up the spline so I stopped before something bad happened. Right now I am in forward on the lower unit, with the prop ratcheting CW and not turning in reverse. While working on the water pump I accidentally turned the shift shaft CW and heard a click.
How do you get the spline shaft on the lower unit to shift back into neutral without chancing tearing up the spline on the shift shaft? Is there a tool such as a spline socket or reverse torx socket that works? Any help is greatly appreciated.
I have attached an image of the sloped cam.

How do you get the spline shaft on the lower unit to shift back into neutral without chancing tearing up the spline on the shift shaft? Is there a tool such as a spline socket or reverse torx socket that works? Any help is greatly appreciated.
I have attached an image of the sloped cam.
