My question is if the upper units were only made for a few years will it be hard to find a used one? I would presume that my lower unit is in good shape and usable. Unfortunately I bought the boat 3 weeks ago and with the assistance of a not so educated mechanic we screwed up and did not add enough oil into the unit. Basically filled it throught the lower hole with one quart then ran it for 10 minutes and locked up (turns tight when starting the engine) the top half of the unit. The boat is a 92 corsair sunbird 185/4.3 and we only paid 4500 for it in excellent condition. It sucks to think that we may have to spend 3500 to fix it. Any suggestions? rebuild? used? Thanks in advance. BTW Phil, I appreciate you setting me in the right direction. Thanks man!! Rob