Model VX225TLRB (2003) with 590 hours on it. It has the original sensor which I have cleaned numerous times (with Yamaha combustion chamber cleaner). Tested the sensor with the test harness two months ago and it was within specs although the voltage at idle was a little high. Perhaps overoiling at idle? This time the engine stopped coming out of the hole like it usually does. It was definately not running on all cylinders. Looked at the plugs and they were oily. Pulled the O2 sensor and there was pooled oil in the bottom of the tube. Checked the low pressure pumps and the top one had a little bit of fuel leaking. I rebuilt it. My question is why does this engine have such a problem with fouling this sensor? I have adjusted my oil rod to specs. I end up changing plugs about every 25 hours. Should I just go ahead and buy a new O2 sensor? My bet is what I've done will get her running again just fine and then 25-50 hours later I'll be pulling the O2 sensor again. I don't drive the boat very fast with the price of fuel. Usually 3-4K rpm is all I run. Could this be leading to my o2 sensor fouling and going through the plugs so quick?
