Re: 1971 50hp Hydroelectric- How much is she worth?
My experience with these motors, is that the hydro-electric shift system can be fine, if the motor was well taken care of. If the gearcase has been properly sealed at all times, and the gear oil has been changed at proper intervals, the solenoids and shifting system will usually continue to work for years to come. If there is a weak point in the system, it is the shift switch in the control box, which often fails due to wear over the years. There are, however, "work-arounds" for the lack of NOS parts for this.
I can't say the same for original ignition parts. I've been very pleased with my 1972 Johnson 65hp motor, but had to completely rebuild the ignition system. In my case, the expense was worth it, because the gearbox and control box are fine, and the motor is in very good mechanical shape.
With these motors, the rule is pretty much - "if they're in good all-around shape, they can be great motors, but if they have been neglected, they can be huge money pits."