1999 ox66 250 losing rpm

[GB250]

got caught offshore today with heavy rollers when engine decided to bog down heavily over 2500 rpms, I had *****ing speed only the whole way back home, engine appears fine at idle. I changed spin on fuel filter while out there with no difference, engine never stalled, I would like to clean and inspect o2 sensor, where is located and are there any parts (eg gaskets) needed to replaced once cleaned. any help would be appreciated.. thanks GB

[jb123]

they are on the starboard side , top, off the # 2 cylinder, looks like a black BOX with a wire coming out of the top.you will need the gaskets unlike thermostats whereas you can hit them down to not tear them. they probably need to be at least cleaned along with the tube. get a manual or look it up online for the specs to test.also , you will need a special socket to turn out the sensor, a socket with a slice thru it to go over the top and wire,maybe the same size as a vehicle sensor socket.

[Ken]

GB,
If the O2 sensor cleaning does not do the trick, then check the local filter for restriction. Also, fuel pump(s) could give you the symptoms you are describing - I think your model Yammie has at least two fuel pumps - if they are at least five years old, you might consider replacing them.
Good luck [img]smile.gif[/img] ,
Ken K

[hooken203]

O2 sensor will not cause that type of problem. Sounds like a warning sensor to me. Like low oil low fuel flow or temp sensor. Not a bad idea to clean the O2 sensor and clean or replace the joint that runs from cylinder wall to sensor.I dont think it will fix the problem though