I want to share some important information that I learned recently while having a problem bleeding air from the fuel system of a Yanmar 3HM35F. I recently replaced the primary and secondary fuel filters in my engine. In keeping with Murphy’s Law, I got air in the fuel system and the engine stopped after about 10 minutes. It was my first experience changing both filters with this engine. Previously I had changed the fuel filters several times on a Yanmar YSM12 and bled the air out of the system without any problem. The manual for the 3HM35F was a little confusing and I was unable to successfully bleed the system and made several unsuccessful attempts to start the engine. Reluctantly with manual in hand, I didn’t want to be a pain in the butt, I went to talk to the mechanic that has done some work on my boat. Fortunately I met him as he was leaving his shop with two other gentlemen. I explained my problem and his first response was that the manual wasn’t clear about bleeding the system and then in about 60 seconds solved my problem. What was stunning was the advice given by one of the other gentlemen to make sure to shut the raw water intake off until I got the engine started. The reason being that while the engine is cranking, the raw water pump is pumping water into the exhaust system. This water is normally displaced by the exhaust from the engine. If you keep cranking the engine without it starting the water backs up in the exhaust system and will eventually will end up in the engine and you will blow the engine. The gentleman telling me this then smiled and stated that the reason he knows is that it happened to him. The mechanic agreed, MAKE SURE THAT YOU CLOSE THE SEACOCK. I think that this would be a prudent step for any raw water cooled engine that was being turned over and not starting