Best "rule of thumb" way to determine future usefullness of an outboard is previous hours of use. On average, an outboard from the mid-90s era is good for around 1500-2000 hours of use, if properly maintained and not abused.
Can seller provide honest number for previous hours of use? If not, is there a warrantee included with motor? If both answers are no, then I would most likely seek a remanufactured powerhead instead of this deal. I would also not get involved with this motor if it has more than 700-800 hours.
For a comparison, I sold a excellant condition 1989 Johnson 200 with low hour(200-300) factory remanufactured powerhead for 1500, including controls, two months ago.
I'd recommend either a remanufactured powerhead, if the remainder of motor you have is in good shape, or a used outboard that has around 500 hours, or less, of use, that hasn't been abused.
Keep in mind regarding used outboards, if they were in great shape, why would owner replace them? Although there are various reasons why peole do replace their motors, usually they are getting tired, or hours are building up, and a savvy boater knows that problems will start happening.
Just my opinions, Mike.
