Cummins 480 CE problem

10 years and 1000 hours? Lack of use issue. I had a problem with the original post (OP), 420 hours on a 3 year old boat. Glad something worked out for him.
Going to be hard to push a claim on a 10 year old engine, Even if there was a (supposed) design problem.

Please (re)read my #18 above.

I like the bit about water in the fuel causing a valve seat failure.

I have read plenty of posts like this on another site. Most production manufacturers are notorious for over-propping their engines to get more speed, and the engines simply can't handle it. My boat has Cummins 450c's, but the 480, as I understand it, is just the newer, electronic version of that engine. They should spin up to 2700-2750 RPM fully loaded in real-world conditions. Any less, they are over-loaded, and dropped valves are a common consequence. I admit I am not a diesel mechanic, just sharing what I have read to try to educate myself....

Didn't see that.