I have a 25hp Kohnler GDLT on a 16x48 Alumacraft jon boat with a 21" transom. When I get up to higher RPMs the prop doesnt want to stay in the water. When I hit something (log etc) underwater, and the prop comes out, it can be difficult to push it back into the water at higher speeds. Becasue of this boat can be pretty difficult to drive and steer. Cavitation plate seems to be pretty level with the bottom of the boat. The guy who sold me the motor said that the back of the cavitation plate could be bent to adjust the ride of the prop in the water. I just wanted to make sure that this was a viable option. This is my first mud boat, so any advise is welcome. Thanks.

There is a bunch of good info on how to adjust the cav plate to get the motor to run a lil better in the water. Use the search feature and look around. If you have any more specific questions, post em up.

is it a tall transom motor?

i had the same issue with my 25 GDLT which is a short transom boat and motor, try bending the end of the CV plate up and the back angled edges down.

Motor is a 72" shaft, and from what I have gathered, not a High transom motor. I'm just wondering now if i should play with the cav plate or just try to tar about 3" off of the transom. I am already planning to take it to the welder for some other work. Thanks for the info

doesnt matter how long the shaft is lt r made for short transom boats ...

Just bend da tab on da back of da cavitation plate up sum more.

You can bend the cavitation plate up and make it work. I am running a 72'' LT on my tall transom boat. I had to go through the same thing to get it to run right. Now it runs super smooth and easy to drive! I did end up notching the 1'' flat bar that is running along the top of the plate so that I could get it bent up enough. Then I just welded up the small notch I cut. Not hard at all though. I wouldn't cut your transom though. You can get it right by playing with it.

shaft has nothing to do with it. it is best on a 16 inch transom, any taller its a bich to keep in the water.

Thanks for al the advise. It looks as though I might have been better off I had the Tall transom GDLT. Given what I have, I'm going to start by bending the last 1" of the cavitation plate up some. I thinnk the idea of notching it sounds like an effective way of makeing bending the plate easier and cleaner.
If I cant make it work after trying several positions, I may go back to the idea of trimming a few inches off of the transom, but for now I will try to keep it simple.

H

i admit i am wrong i didnt see where he had put the 72" shaft. but i have no clue why the prop would still want to come out of the water if its a tall transom motor. bending the cavitation plate helps but not a lot. never did for me anyway. a fresh prop is harder to keep in the water than a new one so maybe thats his problem

I admit I was wrong too. I should never argue with a genius. I guess all the 80±" shafts I've had from not only Go-Devil but Mudbuddy and Beavertail also was a figment of my imagination. Sorry boss!!

who are you refering too as genious and boss?

The guy I have been arguing with.

I'm not sayin da 8_" shaft model does not exist. I'm sayin they weld da cavitation plate on da 72" shaft models at different angles for high and low transom models.

This is what I did with mine after talking to Coco at GD.

I ended up notching the cav plate on both sides and bending it up different degrees to try and fix the problem. After bending the tab enough to keep the prop in the water at high rpm, i found that the prop would drive straight down In to the mud at slower speed, which was also very annoying. I tried 5 different angles over 2 1/2 hours and I never could find a sweet spot to both keep prop in the water and keep it from driving to the bottom at slower speeds. I turned my frustration toward the transom with a plasma cutter and a sawzall. The transom now sits just under 17" tall. I ran the boat this weekend and it ran great. It was a lot more work, but now the boat is much easier to drive, and even runs shallower.