I have a 1994 Four Winns Fling Jet Boat with an 115 Hp Johnson/Evenrude engine. When I bought it used it had NGK Br9hs 10 plugs in it. I am not sure if these were even the correct plug for that engine. I just replaced them with NGKBr9hix Iridium IX Plugs. I have not yet tried to start the boat...