Re: 225 ox66 problems...
Had the same problem...it was the 02 sensor. I've got twin 250's (98's) and have had to replace 02 sensors on both at one time or another. Rodbolt is the best...from my perspective I would put making sure that 02 sensor is good as the first priority of his suggestions. I got frustrated cleaning and trying to find someone who knew how to test, so I just plunked down the $275 for a new one, and got lucky I guess. Also, those motors do idle a little rough as they drop a couple cylinders at idle.