2003 VMax ox66 issues

Guys,
this past fall I had a new powerhead installed on my 03 200 ox66. Although I started the breakin period with additional oil in the gas in early March, competitive kids sports has just now allowed me to complete the 10 hours of break in (boat has maybe been in the water 5 times since I got it back). Saturday, everything was fine until I was running down the lake and the motor seemed to develop a miss and started surging. Almost felt like it was running on 5 cylinders. Max RPMs would only reach about 4200-4400. I shut the motor down and then started it back up. Idle was rough and you could tell something wasn't right. Tried to get the boat back up on plane and it struggled but eventually got it there with max RPMs again at 4200-4400. Could it be the o2 sensor has carboned up with the somewhat delayed breakin running additional oil in the gas? I pulled the plugs when I got home and they look fine. Any suggestions before I have to take back to the dealer? Thanks. Steve

[boats.net]

I would try a new set of spark plugs.

another question

do you think in addition to the plug change that I should go ahead and run a shock treatment of ring free through it as well or not?

[jb123]

hopefully the sensor was cleaned and tested with the new head and shouldnt be carboned up yet.

besides plugs, look at the exhaust when running for any unspent gas, which would mean bad lp fuel pumps.

Thanks

I'll make the changes mentioned above and will keep you updated.

update (kind of)

put in new plugs, added appropriate amount of Ring Free to new tank full of gas, and watched exhaust while running (nothing out of the ordinary - no unburned fuel etc.). Problem still there. Have since taken to dealer for further diagnosis and still on the month long waiting list to have them look at... frustrating. I will post an update when I hear one (maybe October at the rate we're currently moving).