I have a 2000 OX66 Yamaha225. It fouls one plug. Changed the plugs, and it one outing fouled one plug. If this happened to you, what was done to fix it. I would like to know what you did to fix it and not what I need to check so I can hit those parts first. I just cleaned VST tank, put in 3 lp pumps. Will clean o2 sensor next. I’m not sure what the plug numbers would be, but if you are looking at the back of the motor, it is the one in the middle on the right side that is fouling. Thanks.