I have a 2002 Yamaha 60hp 2 stroke motor that I can not get started. It has been running perfectly fine since I have owned it for the last 3 years. I have replaced the spark plugs gas tank fittings and pump(ball), hoses, drained the carbs and cleaned them, and it will not get going. It cranks but will not turn over. If I spray started fluid in there it will start but will not stay running. Any input helps!