Reliability and simplicity in the 40-55ft range?

I do this on all of the boats I manage. I run the engines for about 30 minutes. I run them up to 1500 in neutral for a few minutes, to sling oil around the top end of the motor and spin the turbos. I also bump them in and out of gear a few times so the gear plates/discs aren't sitting in the same place in oil.

Captj, I thought you would have a solid maintenance plan. Had not thought of bumping gears, good ides.

My wife and I will be happy to fly down to Florida to run any boats that need exercising this winter! Mine has spent over half it's life dormant, waiting for summer in Canada. I'm stretching my season from April to October, still a lot of time sitting, not much we can do about it unless we buy an icebreaker.

New member, just reading this as we are looking to upgrade/upsize for longer, farther cruising. I'm a big simplicity, less computer/technology, and duplicity fan as well. Actually looking at two similar OA 548, one with cats and the other with 485 hp DD 6-71 TI turbo with 5500 hours but 2100 since the last major overhaul. I like the idea of a simple 2 cycle diesel, but a little skittish about running them 12-14 kt and going through overhauls (mostly cylinder kits from what I read?) every few years.

If you run them at cruise every 6 hours for 30 minutes they should be fine.

Thanks. Meaning don't push them full time but run lower rpm at 8-9 kt most of the time. That's generally the feedback I'm getting.

They're designed to run at cruise, this is what the D.D. dealer will tell you. But, if you want to run them slow (1000 rpms or less), then run them at cruise or even slightly above cruise for 30 minutes every 6 hours to clean them out as D.D.'s get slobbered up when running slow speeds all day.....

Very cool. thanks for the information once again! I'm so used to the Cummins 370B's in my current boat and other 4 cycles that these 2 cycles and some of the horror stories had me spooked. Nice to know that if these are taken care of and run well they have plenty of lifetime left in them!

6-71 TI's are great motors and most people see 10,000 hours before rebuilds on them, usually 5,000 at a minimum. They're not as clean as the 4 strokes, on start up, oil leaks, etc. But cheap to operate and proven.