I have 1997 Sugar Sand with a 175 Mercury 175 Sport jet Engine. I just got, and it has been really hard to start, I had attached a external water source to test the engine, when I pulled the plugs I noticed water comming from the bottom plug on the Right Bank, no other plugs. Suspect a blowen head Gasket, could this be the caused and was it posable that the gasket blew because of overheating by a defective Thermostat?