I have an 01 X19 w/ 01 200 vmax, 25M prop, and 6". I found out today that I have only been running 5 cylinders instead of 6. I new something was wrong for a while because I was only running 4500-4700 rpms. However, it would start and run fine for the most part. I cleaned the o2 sensor, new plugs, tinkered with the jack plate, almost tried another prop. I was just about ready to take into the shop this week to have it looked at. Before doing so, I thought I would look at the plugs to see how they looked, fouled etc. I unscrewed the first plug from the 1 cylinder and noticed it looked spotless, like new. So, I moved to the rest and you could they had been used. Next thought....bad plug wire. Nope.... Looked up and a small black wire had been unplugged. We test and made sure it was getting fire when it was plugged in and when it wasn't. Sure nuf .....that was the culprit! When changing the old plugs didn't think much of it. Man, did I feel like a dumbAZZZ 
OH WELL! I will get back on the water this weekend see how much diff. it makes and will post info
I was able to hit 68 mph and let off. I am sure I could get the mid 70's out of her. It was real windy today so I wasn't able to play around with it too much.