Ok, I have a new Alweld 1648 mv jon boat 16" transom. I have a 23 hp go devil longtail. The motor wants to jump out of the water at full throttle. Note, this motor came off a 20" transom boat. I have bent the cav plate up 45 degrees from flat to get it to stay in the water and it works well at 3/4 throttle, but at full throttle it jumps out. Should I bend it up more, or should I raise the transom mount an inch or two to compensate? I am an experienced welder, and have thought of re-welding the cav plate to the correct angle, but I don't really want to do that unless I have to. So many variables. I have a feeling it will be a trial and error thing more than anything, but if you have any advice, I would greatly appreciate it! thanks...

If the motor came off of a 20" transom and you are sticking it on a 16" it might be the extended mount that compensated for the 20" figure this part out first and make sure you have the correct mount for it. What i imagine is you bending the whole plate up to a 45 which would not be good (the motor would likely dog with more drag than required)... ok the cavitation plate should be good where it was set (unless the mount if different see above), at the very back of the cavitation plate there should be a bit of metal sticking out, this is the trim tab. Take a crecent wrench and bend that tab up 1/8th of an inch at a time until you get the plate to ride just under the water at WOT. The water flowing over the plate and having to ride over the raised trim tab will keep that cavitation plate in the water. Same would go for if it wanted to dive at WOT, the water running under the plate contacts the part of the tab pointed down causing lift.

This^^^. It's trial and error , keep at it bending a little by little and it will find a sweet spot .

ok sure, that's what I meant, the tab is at a 45 right now. I will keep adjusting it. thanks guys!