Re: nissan ns 90a won't go forward
Two problems in one unit. The water is from a seal or o-ring leak; The shift rod issue may be a mechanical problem.
I would reseal the LU, including driveshaft seal, propshaft seal, and shift rod o-rings. While at it, it may prudent to replace the impeller (or whole water pump kit), since you have already done all the labor. While you have the LU down, you can investigate the shift issue.
You may have a jammed shift wedge or clutch dog -- or for that matter, a misaligned neutral safety mechanism. Keep in mind that the prop shaft must be turning in order to shift. If the motor is not running, it's entirely possible to be unable to shift, yet the mechanism can be OK.
A parts catalog is available on Elvin's site at
http://www.internetoutboards.com/PartsCatalogMenu.htm and that should show you all the various linkages and seals that are involved.
The Factory service manual is pretty comprehensive, even detailing how to check/adjust gear lash. It does assume that the technician has enough basic mechanical skills to do the work already. The shift rod travels up and down, causing the push rod (internal to the propshaft, and spring loaded) to travel fore and aft, allowing the clutch dog to engage either the forward or reverse bevel gears. If for some reason, the stainless roll pin came part way out of the shift wedge, that might prevent the rod from coming up all the way. A thorough inspection is a good idea to troubleshoot, diagnose and repair the problem.
