I am still less than a year into ownership on 2007 387 with a 3JH4E with 3760 hours (3700 when we bought it). I've pulled the heat exhchanger off and took to an experienced Yanmar mechanic for service. He found it in poor condition with serious corrosion that resulted in a small hole through the exhaust port to the cooling jacket. My engine had been running a little hot if I got it over 2600 rpm, but at 2200 rpm (which is where prior owner told me he liked to run it) it runs normal temp. The bigger issue is that he is suggesting the exhaust hose routing from the mixing elbow to the muffler is a serious risk to the engine in certain conditions - mainly running the engine, shutting down and putting up sails, then getting into really rough seas with pitching that can lead to water running into the manifold and cylinders. He is suggesting searching for a Centex muffler that I can put closer to engine so that there is no exhaust hose sitting lower than the muffler after leaving engine. I get where he is coming from - he's seen lots of engines hydrolock - but I have no intention of trying to sail in seas that are so rough that I would deal with this risk. I would be sails in and engine running long before that! A lesser concern is the premature corrosion over time of having sea water sitting too close to the manifold/mixing elbow? If I'm maintaining the system periodically, seems like I could mitigate serious corrosion over time.
Anyone done any sort of modifications to the exhaust routing, or am I making a mountain of a mole hill?? Thanks for any input.
Anyone done any sort of modifications to the exhaust routing, or am I making a mountain of a mole hill?? Thanks for any input.
