Decided to do an analysis on our workboat. Its a Parker 3420 XLD with twin Yam F350s. The work that we do involves a lot of idle time and low rpm cruising, I would estimate about half of the OCI hours are idling, but, when we do cruise I like to run it wide open. Boat gets about 250 hours a year since we have owned it. This is the first analysis it has had though, as I was starting to get concerned that the port engine was making oil. I change the filter every other oil change and cut them open and have never found any sludge or metal. This oil had been in for about 6 months.