I Have A 60 Hp Mariner 89 Model. The Motor Runs Fine Kind-of When Hooked Up To Water Hose But Not Under A Load In The Water, Will Run 5mph .i Have Found That 1 Out Of The 3 Plugs Has No Spark Or Tryes To Spark But It Is A Weak Spark Then Won T Fire At All. The Plug Is New. Could This Be A...