similar thread from 2 years ago. looks like the OP ended up getting the factory involved . . .

link

No problems with porpoising on my SHO 250/ FX21LE
I'd have a Skeeter rep ride with you.

The vibration could be a bent prop shaft or maybe 1 or 2 cylinders not firing, causing the vibration and the inability to power through the porpoise.

I've had three Skeeters over the years. The first, a late 1990 version ran fine and fast with no porpoising. It was a bit unstable and chine walked at high speed. I owned an infamous 2006 20I that at first porpoised at all speeds. I returned it to Skeeter and they fabricated and added the rear-end "down flare" and it improved the problem greatly but there was a speed where at higher trim where it porpoised. When it happened, I just trimmed it down. I bought a 2016 250 ZX and it runs great at high speed and high trim but also has a speed where it porpoises. I just trim it down to stabilize. The greatest difference I see between the ZX and 20I is the ZX seems to have a lower profile off the water at high speed. There is not as much movement of the bow up as the trim comes up. It still planes at the back of the pad and is in my mind an overall more stable ride. I think all Skeeters porpoise at lower speed and high trim.

I'm running a new zx225. There was a bit of a learning curve with it. Very trim sensitive. Don't trim up too early and trim down before you slow down.

What type of motor toter do you have ? Do you have a motor-mate if so, did you take it off before launching ?

Ok I talked to my dealer and they said to bring it in. I took it over to nautical mile where I purchased it. The owner met me out front took the boat around back fired it up for a little bit. Checked the throttle linkage. Turned to me and said lets go to the lake. He took it out for a spin came back picked me up and showed me a lot about how to really use the trim. There was no problem with the boat. I did have a weight distribution problem. But he showed me what to do to get it right. He also spent some time showing a lot on my electronics. Biggest problem was me and babying it too much. As he told me "you have to let the beast out". I will have to say the guys at nautical mile have been great. And that is saying a lot after dealing with someone as hard headed as me. Thanks for all the advice that everyone has offered. Most of the problems were in my head, and mentality driving the boat. So yes I will admit it was me. And we turned a top speed of 71.6, so now that I have admitted ignorance, I am very happy with the new bug, and extremely happy with Nautical Mile Marine.

Glad to hear. That little bit of time will pay big dividends in your ownership experience! Enjoy your new Bug Boat!!

I call it the trim dance. It is not a set it and leave it thing with mine unless I am doing WOT. Even then there can be tweaking depending on what is going on with the water. When mine porpoises I know I am off on the setting for the speed. I agree with the dealer about letting the beast out. I have the older Ox66, and it likes to run.

Awesome!
I remember when I came out of my 18 ft champion with a 150 to a 20ft Skeeter with a 225 I was a little throttle shy too, but got over it pretty quick!

That's me going from a 18 ft skeeter 86 model to 05 ZX225 with 225 that's a little getting use to

I bought a zx20 this week.... I learned quick keep trim down until you want pure speed

Took mine out again today. Funny how much better a boat runs when you are mentally relaxed.