Question on 02 sensor

[KWP]

The motor is a 2000 200hp efi ox66 and I am having problems with a high speed surge. I pulled the sensor , the block it screws into and there was another part that slid into the block, everything was carboned up really bad. I use Yamalube and Seafoam but now I am concerned about the inside of the motor, would a shock treament be advised or what else should I do.

[jb123]

Clean both as best as you can and then test it

[Sequoiha]

i would quit using seafoam and start using ring free,,, good stuff, even if you have to use a drill bit make surt the transfer tube is very clean... you might even want to check the electric fuel pump,, there is a resistor on the top of the motor just above the vst and ive seen lots of these connectors get dirty and loose connection.