97 Nitro 75hp Merc won't plane out

[Greg Smith]

Hi..I recently took my boat out on a lake and it ran perfectly for two days.After a few hours,and a brief rainstorm,I took the boat out again and it would not plane out.With the throttle wide open,it would only get to 4000 rpms.Was hoping the next morning all would be well,but the same thing occured.I did leave the boat parked in the water entire time on trip(3 days),and the prop did get in the sand,but only on the surface.Also,while there,I used 89 gas from the marina,while up to then I had only used 87.The oil mix is 50:1.Could anyone tell me what may be the cause of sudden loss of power and could any of the factors mentioned above

 

[LubeDude]

Re: 97 Nitro 75hp Merc won't plane out

the prop did get in the sand,but only on the surface.

If the prop is aluminum, you could have messed it up more than you think, try another prop and see.

Check your plugs to make sure you didn`t plug up a carb and you are running really lean. The lean cylinders will be very white and clean. You could blow your engine if you continue running it this way.