valves

Reaching out to anyone who has been able to fix problem of minor soot developing on hull after 50-60 hrs of cruising Hunter 44DS 2004 Yanmar 4JH3E 2400 hrs (1500 hrs added during last 27 months) no visible smoke engine runs very well and starts immediately WOT rpm 3800 Cruise rpm 2800 (75% of...

Morning everyone, *Edited post* Thank you for the replies so far. I should have said that I have already traced the lines, most of which are not visible, and I remember the valves being extremely hidden. We only found them during the sea trial by lucky accident. So if anyone knows off the top of...