Re: 1969 Johnson 55hp Hydroelectric no forward movement
I'm going to defer to Joe & DHadley on this because they have much more experience in the matter than I do.
That said, I guess my instinct as a fomer aircraft mechanic, and someone who has worked on a variety of engines/vehicles (including many outboards) over the years, is to try to think through problems logically. Where I start is with the fact that the motor was purchased, run for one season, and then winterized and stored for many years, until you began to use it. Assuming that there was not an incident during that one season of use, which could lead to suspicion of mechanical damage, it is logical to think in terms of problems that are time related, ie: what things could be affected by a long period of inactivity?
One of the things that sometimes happens with these motors, is that the wiring that runs from the lower cowling to the gearbox (internal midsection), becomes brittle with age. This tends to cause problems with shifting and can be a significant problem because the part is no longer available. The advice that you received to disconnect the wiring at the connectors located on the port, rear side of the motor is good, because it allows you to include or dismiss that potential problem. Given what I have read so far, I don't think your problem is electrical.
As you may understand from this discussion, your motor defaults to forward when there are no electrical and hydraulic inputs to shift to neutral or reverse. Electrically, what happens is that there is no signal for forward, signal to the upper/neutral solenoid to select neutral, and signal to both the upper and lower solenoids to select reverse. From a mechanical/hydraulic viewpoint, there is a spring in the prop shaft which exerts pressure on a piston, forcing it forward into the clutch dog. As I understand this gearbox, it is that spring that causes the motor to remain in forward, unless hyrdaulic pressure is exerted to move it backwards to the neutral or reverse positions.
So, what could be happening? In my first post, and the "PS" that I added, I went from suspecting the spring to wondering about the screens. At this point, I don't think it is the spring, because (and as DHadley pointed out) the motor is locking in forward when it is not running. This means the spring is exerting the proper pressure and the piston is able to move fully forward. I am now thinking something else, because I am learning as I research this problem. My manual shows a diagram of how these gearboxes work (figure 6.5, if anyone has the 1972 65hp book), which is helpfull because it depicts the function of the ball valves in the pump. In short, they are held in the closed position, or allowed to open, by the solenoids. While your problem could be related to a need to adjust the solenoids, I wouldn't think that would be the problem in a motor that was only used for a few months.
What does make sense to me, and I think may well be your problem, is that 38 years of inactivity has caused the gear lube to thicken and "gum up." I'm not sure what the lube would do if it were in a sealed container (with absolutely no air in it) for all that time, but I wouldn't think it would take much air at all, to cause a change over so many years. If my guess is right, I can easily see one or both of the ball valves sticking a bit, resulting in improper oil flow. Very thick, gummy oil might also prevent the pump from operating properly.
Even though I have written "a book" here, as I have a tendency to do, I think the bottom line is that DHadley was on to something, when he suggested that the plunger (piston) isn't moving as it should be. I think he is right, but am not sure of exactly why that is so.
At this point, if I were in your shoes, I would think in terms of cleaning the gearcase out. I don't know if this can be done without taking it apart to clean the individual components. If it is possible to run some sort of solvent in the gearcase briefly to remove deposits, you might have a simple "fix" available. If this shouldn't be done, you may have to take the gearbox apart, so that you can clean and inspect each part. Hopefully, one of the guys will know which is the proper way to clean the parts. If this is not the case, you can always consult your local OMC/BRP mechanics.
My personal opinion is that you should not run this motor further, until you fix the problem. I believe that the light "ticking" sound that you are hearing is the clutch dog making light contact with the inner portion of the forward gear. You may not have caused any damage to the dog and/or gear at this point, but if you keep testing the motor you may.
