I have a 200 EFI ser# OT148526. On an outing about a month ago, it took off from the ramp like normal, and ran fine. Later that afternoon it started not wanting to come up on plane, and would only top out at low 50's, where it would normally run mid 60's. On that day it seemed to be running rich. After bringing the boat home, 2 of the plugs looked fouled, so we replaced all plugs with recommended (NGK's I think). Running on a hose, all cylinders tested good for spark. I took the boat back out, and it still didn't want to come up, and ran slow again. I brought the boat back, made sure all battery connections were good, and tried to look at and insure all harness connections were solid, but the boat is still running the same. My tachometer was reading high in the few outing before all this started. The day all this started, my water pressure gauge was showing high as well, I did not get any alarms though, and the alarm does chirp when I first turn the key. With the tach acting up, I thought maybe a bad ground, but haven't found anything yet. Motor doesn't sound bad like it is missing or anything, just has not power. I need some ideas as to where to check next, or what might be causing this. I plan on checking compression next, just to hopefully rule anything in that realm out. Any ideas or help would be greatly appreciated.