I have a 20 year old Yanmar 15hp in my 34 Irwin and recently had problems starting it after not using it for 3 months. I used starter fluid to get it going but it is now puting out grey smoke and black carbon looking particles in the exhaust water. It will only start with the throttle in full open position then quits after 45 seconds. Any thoughts? Also, does anyone know the proper fuel bleeding procedure on this engine.