A buddy is considering moving from a SeaRay 420 to a 48 Ocean Alexander with 500 hp Yanmars. He has Cummins 480 CEs on his 04 420 and actually dropped a valve seat at 700 hrs... Ouch! I saw a thread on the Yanmar 440s about serious valve issues. Does anyone know if the problem is limited to the 440 HP engines? Cummins had big issues with the 480CE and corrected when they went to the 500QSC later. Thanks
I think the 6CXM's are rock solid, apart from their cooling system (dissimilar metals, or something like that), which might require more attention than otherwise over the years. A google search will shed some light there. They don't have that valve issue you mention for the 440's. Good luck
we have the 465 hp versions in a 43 Ocean, and so far have been happy with them. The cooling system appears to be quire robust, just has about a dozen anodes, so keep in top of those. At one point I found the temps were creeping into the low 180's while at cruise, found I only had 3 out of 7 blades left on the impeller, I know shame on me for not checking impellers more often. Also I see that this model is not offered in pleasure rating anymore and is only sold as a commercial model which is encouraging.
The valve issue was for a certain number of early serial numbers on the old 440hp Yanmar. Still a good engine, but if you are buying a boat with these you must determine if the valves have been replaced, generally a swap out of the heads.