Loss of power question

[PensacolaJason]

I'm having a weird issue with my boat where it runs great all the time except for when I go over a large wave. It seems to happen most often when I am heading in the same direction of the waves. As I go over the crest of the wave and come down it seems like when this happens the motor may come too far out of the water and the motor will over-rev and then I'll lose full power for a bit until I back off the throttle for a few seconds. When I re-engage the throttle it goes back to normal. I don't know a lot about ventilation or spun hubs or whatever might cause this, but was wondering if this is common and if there is something I should be looking at to keep this from happening. Going over waves or swells is just par for the course when fishing, so I'd like to figure out what causes this.

I've always thought my motor might be up too far on the transom. I will post back some pics when I get home from work and hopefully you guys can let me know what you think. One questions surrounding this topic, I know the bottom of the boat should be about even with the cavitation plate on the outboard. And that people will run a straight edge along the bottom of the boat to see if the motor is at the correct height. Should the motor be trimmed all the way tight to the transom of the boat when determining this?

My boat is a 19.5ft 1995 Key West Sportsman 1900 with a 1984 115hp Johnson.

 

[alldodge]

It seems to happen most often when I am heading in the same direction of the waves.

Seen the big waves that surfers ride? The waves get high enough to brake over and there is all kinds of turbulence and air bubbles. If the wave does not brake, the surf board will brake the top over as it comes over. I think whats happening, is the boat is doing the same thing, its creating the turbulence and the prop is ventilating.

It doesn't do it going against the wave because the water is being pushed against the boat/prop.

To prove it out, when it happens, pull back on the throttle enough to keep it from over reving, then leave it there and see if the prop takes hold again and moves on.