gamefisher slows down

[MichaelMullis]

I have a 1992 15hp Gamefisher. Had it serviced over the summer and went fishing labor day weekend. Motor ran fine on day 1. On each consecutive day boat went slower and slower. Motor sounds the same, rpms seem to be same but boat goes slower. got so bad by 3rd day I had a friend in a pontoon stop and we tied my boat to his so he wouldn't leave me alone on lake with storm coming up.Motor cranks fine, runs smooth, Idles smooth. What could be wrong? I use to have this motor on a 14' alum and it ran about 20mph, now on 15'DURACRAFT and runs maybe 5mph.

 

[Fouled Plug]

Re: gamefisher slows down

If your RPM's have stayed the same, I'd suspect a spun prop hub.

 

[MichaelMullis]

Re: gamefisher slows down

Looking for a repair manual for a 1992 15hp Gamefisher. Also will need points, condenser, ect.Checked plugs yesterday and had 1 plug not firing swapped plugs and still no fire on same wire. wires seem ok but I know everything is original, figure what the heck I mite as well do a complete tune up. Had carb rebuilt past summer, new plugs. What should gaps be? All advice welcome.<br />Fouled Plug, checked the prop, it's on a spline shaft and both splines are in good shape. thats when I started looking at other things. Thanks for advice. I have never worked on a boat engine before so this is a new one for me.