I've got a 25hp Go-Devil long tail that is not getting up to rpm. I have it set at wide open out of water at about 4200-4300. However once in the water and under load I can only reach about 3000. Only getting about 10 mph out of my seminole bateau. Back before this past season I was getting about 18 with the same load. I have changed from a backwater prop back to a Go-Devil. I expected to lose a little speed, but not this much. The issue with the speed started before the prop change. I've tried to fool with the governor, and it seems to be getting what it should without a load, but once a load is applied it all goes South. Any help would be great.


Side note: I believe there is water in my hull. The project of cutting out the decks and completely redoing the boat is about to start. Took boat out today for baseline numbers, and was reminded of this motor issue. Please help!

You have too much prop for the motor to spin by the sounds of it. There is a fine line with these small motors when it comes to their ability to spin a prop under load. Try the smaller prop again and see if it picks up the RPMS then you will know it is not a motor issue for sure

another thing you can do to rule out other issues . Run wide open and ever so gently pull the choke out, it will either gain rpm's ( high speed jet clogged) or stumble. If it does not gain rpm before it stumbles it is too much prop. good luck.

Go back to the old prop?

B. MacDonald