It appears that water is getting into one cylinder of my 200 HP Yamaha ('96 model used in salt water) Even a new plug will foul after several hours of running. It is the top plug on the port side. All of the other plugs look OK.<br /> I have had this boat for 9 months now. It worked fine until about 3 months ago when the plug started fouling. My inclination is to remove the head and see if I can find the source of the water. So my question is:<br />Any special considerations/techniques to removing the heads on a 200 HP Yamaha? It appears to be straight forward. Is there a particular sequence for removing (and replacing) the head bolts? Any assistance will be greatly appreciated.