Re: What's my 98 150 hp mercury worth?
Well, good on ya for trying to get this matter resolved. It can be taken as a big deal if you were to have an oversized motor on your boat and have an accident. I wouldnt stress it too hard though. This is ALL opinion here, but if it were me Id probably ride it out for the summer, and worry about fixing my oversized motor issue during the off-season. Id definitely tell your insurance company and see what they say. I think owning a boat and not having insurance is INSANE. By the time you sell this motor, get it off the boat, find another motor, mount it, and NOT run into any motor issues with the "new to you" motor that you buy, it may be well past boating season. Another route to go would be to sell the whole package and buy something else.
Back to your main question, not sure where in the world you are, but I am in VA, on the east coast. A "salty" 98 150hp merc would probably carry a $2500-4000 price tag in my neck of the woods. This is assuming that it is in good cosmetic condition, and that the bolts aren't rusted shut on the head, and lower unit. Hard to put a direct price tag on it, not knowing the compression of the motor and other aspects.