Realize I am responding to an old post but having the same issue on my 92. Got it out for first run after winter and ran great all weekend, that is until the last run of the day. At that point the boat started to lose speed and RPM and forced me to come to a stop. It never died and when I would accelerate again, all was good and it would run but then randomly lose all speed and come to a stop. Initial start-up was fine and idle was fine, though admittedly as the day went out, I noticed cold start each time we went out would require me to give it some gas in order to stay running.
I have read on here about spark plug changes, fuel pumps, etc. I did winterize it and treated the gas. Tried to run most of that old gas out before refueling. Did not do a tune-up this spring as I had done that last year.
Any thoughts based on this? I know there are many things to begin analyzing and I am not mechanically inclined. Boat does have perfect pass and therefore has the dial to set the right tension for the throttle cable. I did loosen that prior to last outing because I was noticing that unless I keep my hand on the throttle, I progressively lose speed as the throttle comes back toward idle. So I did wonder if that adjustment had anything to do with it.