I have a 2003 225. When I first got it I had trouble with the O2 sensor. I left my motor trimmed down after I had turned it off. Apparently water siphoned up the tube to the O2 sensor. I was not able to get it started again and I had to replace the O2 sensor. The replacement had a longer tube so that the old problem would not happen. But I was told that if I had trimmed the motor up when it was off I would not have had the problem in the first place. So I always do this. But my question is, do I still have to trim the engine up even though I have the new improved part ? Reason I ask is that I am selling the boat and I want to make sure the new owner has the correct info.
Thank you

The engine should be mounted so that the exhaust relief holes (the two holes in the back of the motor) are at least 5.9 inches above the water. This is to minimize the amount of water that goes up through the exhaust to the O2 sensor and to the cylinders.

Water can get in there from a large trailing wave, or if it is docked and it is in the postion for the motor to get hit by waves. You just do not want water coming into to those holes.

Mike