Originally Posted by
Genesis
Capt, in a commercial boat I'd probably go do it, because its better to do it "on plan" than not, and when you're putting 500 or 1,000 hours a year (or more) on the motors having to do it mid-season is unacceptable.
But in a recreational service vessel? No. Not now, IF the rings are ok.
If the kits grind themselves over the next 2-3 years, they do. Why spend the money NOW? If they're running ok and starting ok, run the boat. Yes, there's a rebuild down the road, but it doesn't need to be done today by any means.
Now if there's a busted ring in there, then you have no choice - the engine has to be torn down.
When I had my 45 I used to be "Mr. Detroit" because I was known around the docks for having both the tools and knowing how to use 'em. I probably looked at a half-dozen boats with exhaust ingestion problems over that time, most of them with airboxes that looked FAR WORSE than this one.
Every one of them the engine shops would recommend an immediate teardown and full rebuild. With those where I could get at the rings to look at them easily and found them not stuck or broke my view was the same - in recreational service if the ports on the liners are unobstructed and the engine starts and runs ok run the boat, knowing that you have likely taken a significant amount of life off the motors - but that the need to rebuild is not here today. Monitor for starting problems, performance problems and smoke that won't clear, especially after the engines are warm, and if you have easy access to the airboxes check 'em annually for stuck or broken rings. If you find ring problems tear the engine down, or if and when they are misbehaving in their operation. In the meantime run oil analysis on every oil change; if there is a SEVERE problem about to bite you in the ass you'll likely find it in the form of sky-high iron and chromium levels (chrome = rings, iron = cylinder kit walls among other things)
Until then go fish.
Of those half-dozen three owners took my view and two had rebuilds done. When I sold Gigabite the three who took my view were still cranking up to go fishing with no material change in their engine behavior a couple hundred engine hours and two or more years later but still had the $30,000 in their pocket, while the other guys had no material change in their engine behavior either but were light that same $30,000.
For commercial guys the advice is different because the downtime can come fast and hard, the hours run annually are a LOT higher, and downtime hits revenue instead of enjoyment. There when you find trouble you fix it at the first reasonable economic opportunity, and winter is a good time to be doing that.