Three things lead to what you have going on.

The first is having rocker in the bottom.  Seriously doubt that's what you have going on, but a straight edge will tell the story.

Second,  too low of an X dimension or thrust line. You can scratch that one off too.

Three,  trim tabs,  ride plate and nozzle relationship all fukkered up.

I would start by raising the ride plate to about 2.5 to 3° "up" from flat to the keel.  This seems counter intuitive,  but try it anyway.

One piece of caution,  that Diverter nozzle looks like an older design. Does it have a reverse chute under it?

A later nozzle can help dramatically.

Also,  while you're dickering around under there,  check for what loader  (if even applicable) you have in that pump.

The JE, JF design is a little fickle when it comes to loading.

Do the rpms seem to fluctuate up and down when she dances?

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Thanks! It has this style loader on it now (pic below). Motor is 454 very mild. Not sure think it has reverse chute but will have to look again. I put 3 foot level on it yesterday & plate is definitely down in back. Did not notice RPM fluctuating at all.

Ok I will check tonite. I also have this grate that came with boat, but was from when it had 600 hp motor. I didn't think I woud have enough HP now for that one.

beautiful boat nuthead. i was wondering where it went. i was looking at that boat right before i found mine. pretty purchase

Correct me if I'm wrong Glenn, but isn't that rife plate a little short? Even for a JE/JF. I feel like they are supposed to be longer. The length could help reduce the porposing

Maybe.  Hard to tell, but it looks like a stock sized plate.

If someone adjusted it down,  it could do some weird stuff.

I have seen shorter plates and certainly longer.

You could totally be on to something.

I'm still sort of thinking that if it was adjusted up it's either going to allow the boat to ride higher and fly the bow a little more,  or be one of the wildest riding bronco, Billy sons a bitches on the planet.

Lol

GT

Checked last night it does have reverse chute at nozzle. The ride plate was set at 4 degrees down. I set it to 2 degrees up now.

So, just so you can come to school prepared.

It might be flighty as hell, so be on the ready.

If it porpoises the same or worse,  try nudging the diverter up a little and play with the throttle. The whole idea is to see if you get get the hull to take a set back on the plate,  this will get the hull to fly a little and ride on the back plate and probably 5'of the back of the boat. If you can get it to settle out,  note where the water breaks from the hull. Is it at the seats,  behind the seats,  just before the engine and so on.

I am pretty sure this adjustment won't fix it,  but we want to see if it's better or worse. In thinking it will be a little better,  but will be a challenge to drive (the faster you go, the better the handling. ).

It's my opinion that the nozzle is killing you just a little. But we should still be able to make it work better.

Don't forget to check the loader biting edge elevation.

Be safe.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Well went to river this weekend. It was way worse with ride plate set 2 degrees up. So lowered it down acouple times and probably back to where it was originally set. Guess this boat just likes the 4 degrees down.

Personally,  I think a later style nozzle with the flat surface on the bottom will make a giant improvement.

JMO

GT

Here's 2 pics while we were cruising up river about 3200-3400rpm

Just going to say it out loud,  you need more down trim.  I think someone had the ram installed incorrectly.

JMO, that thing is trying to fly way too much boat.

looking at that first picture, the diverter looks all the way down, but it looks like its straight. (could be the picture)

But yes that thing is trying to seriously air out.

Im with glenn, try switching the ram around.

Or do you have a better pic of the ram?

I will get better pic of the ram tonight. I'm new at this stuff so not sure how its supposed to be. Looking at pic not sure how else to install ram?

just flip it over if thats the issue.

Here's closer pic of cruising 3200-3400 rpm diverter mostly down to not porpoise. I will get pic of pump tonite.

seems to be a lot of lift for only cruising especially with the diverter down