Re: 90 hp force
I had the same motor on an old bayliner I had. The water pump is a pain to replace by yourself (although I've done it) only because of the weight of the lower unit. You have to disconnect the shift linkage by the power head, remove the bolts that hold the lower to the upper unit (I think there are 5 bolts if I remember correctly), then slide the lower unit off. It's a little bit tricky installing the new impeller, but not impossible, just make sure the blades are facing the right way. Also check the housing of the water pump to see if it needs replaced. Getting the lower unit back on is where a second set of hands works out great. If you have any mechanical ability, you can figure this out. It aint rocket science...
Do you have a manual for the motor? I'd get one. They don't cost much and pay for themselves in the long run.
