i upgraded from a 9hp to a 16hp and with the old prop for the 9 and the new bigger one for the 16 the 16 is wanting to blow out and wont stay down at top end the trim tab is bent up but still no help i have just been running it surface driving but it gets tiring after a long ride my question is could the frame be unbalanced now since i put the bigger motor causing it to be front end heavy and has anyone shifted the whole frame back further and remounted it to the swivel bracket i was thinking about trying it but wanted to get some input on it before i drill a new whole in my mount plate???? thanks fellas

How tall is the transom on your boat?

Is this the same boat you ran the 9 on?

It appears the shaft length is the same for the 9 and 16 frames, so the only thing I could think of is maybe your transom height is wrong, and the 9hp wasn't strong enough to discover the issue.

its a short transom like around 14 inch maybe its a 1436 alumacraft from academy

same boat for both motors also all i did was took one motor off and put the other one on

Mine did the same thing... I went from a 9 to a 10 then to a 23 all on the same frame. I had to make a new pivot point. I'll post you a picture later if you'd like.

yeah that will be cool i figured that was the problem i mean i can run it like it is but like i say for long trips its gets to be work lol

The prop is just turning more RPM's and creating more lift.

While the motor is running the weight of the motor won't affect how it stays in the water, only when you are slow rolling or stopped will it come out of the water.

Bend the cav. Plate!

superdave how far back did you have to slide it back

never had a chance to take it out and try it since i remounted the motor on a new pivot point but changing my upper brass bushing out to a roller bearing is working great no more heat on the upper end of the shaft sorry it took so long superdave with the pics just been busy with work

JP lookks like you did a good job. By looking at it you might even need to move it even farther back by going with a bigger motor. But you won't know till you try it out. I will tell you that I thought about using a clamp style u-joint yoke but went against it because a driveline shop told me that it would cause too much vibration because of the offset bolt for the clamp-makes sense. If you notice any vibration that might be where it comes from. Good luck, and if you have to move your pivot point again, drill several holes just in case you need to move it even farther.

yeah it ran alot better than before still wants to come up at full throttle but my cav plate is straight right now im gonna bend it up a lil and see if it will be enough as far as the coupling that is a stock from go devil but it doesnt seem to cause any vibration

I made my own with a 9hp by copying a 16hp gd frame. i moved the motor forward 2 inches and i got it pretty well balanced. But i want to go more with cavitation plate needing more bend up. friend did a 16 to a 23 upgrade on his and it did the same thing as yours, and as far as i know the weights on the motors are the same, so not a balance problem.