No Repower - Rebuilding Mid-Season

If you major them, you won't end up repowering for a long time. If you REALLY want to repower, I would just do it rather than major one. It's a tough decision but depends on what your wants are. Rebuild is quicker and cheaper. Repower is a faster boat and what you really want, so you lose part of the season.

He will probably keep the thick end of $100k by rebuilding vs repowering, that buys a lot of snacks to eat on the way there and back at a few knots less and bait for when you get there

+1 ...more than $200k probably.

It's true, it's much cheaper but he has been researching re-powering and talking about it for a while now and really wanted to re-power.

Good luck. Nice to see others having 4K hours on a 92. Was there anything you can think of which may have prevented this failure?

For day dreamers & inquiring minds, did you ever decide on a re-power package?

Your decision will at least add more value to your engines resale. If and when you do the repower.

Any autopsy on what happened?

Over revving thru the surf chasing trap raiders?
Over pushing an iceberg out of the way and a floater blocked the water inlet just for a second or two?
Ah, fighting and backing down hard on a trophy fish for 10 hours?

Of course, it just didn't break down by itself..
Or did it??

Looking forward to good news tonight or tomorrow.

Whoa
21 years on same piston. Guess that is a good record. Bless it's heat.
My excuses just sounded more fun.

Of course when I have a failure,,,, It's never my fault. Those darn aliens were up to something again...

Dockmaster,
Although, I am a little late to comment... you did the right thing. Considering your use of the boat in hours per year; satisfactory operation with the current set up in good condition; the condition of the other engine with break in hours basically; and; problems and expenses with re-powering. Best choice.

The issue with the rings sounds to be combination of use and design of the basic engine. You are a light user with long periods of between use and long, many years of use, but good maintenance. The engines like to be run for long periods at power for best life... just not without maintenance and at high outputs. I think you just got some ring sticking from the accumulation of deposits, lack of lube and periods of non-operation. This conspired with the overall operational long term setting to result in this problem... bet it happened in startup or shortly after. At lease it was not catastrophic where re-power would have been you only real choice. Either the C18 or MTU v-10-2000 would not have faired better in the identical situation. The only question I have is what kind and what oil was used and how often changed was it over the life.
See diesels like what is termed high ash oil but this is a misnomer because it refers to the anti-friction additive for prevention of cam and lift wear... what I think is critical in you use, particularly with Detriot 92's is what is called soot related viscosity increase and shear in diesel engines a description of potentially your ring failure cause... these in API are "C" rated oils. An intermittent use you might be better with a low ash oil. Of course manufacturer guidelines are important to consider.

I just am thinking... here is the description for API website:

"The “CI-4 PLUS” designation identifies oils formulated to provide a higher level of protection against soot-related viscosity increase and viscosity loss due to shear in diesel engines. When originally introduced, CI-4 PLUS identified CI-4 oils meeting a higher level of performance. CJ-4 oils include all CI-4 PLUS performance requirements. CI-4 PLUS appears in the lower portion of the API Service Symbol “Donut.” "

Factory states CF-2 ONLY and single weight.
The newer oils have newer ratings and updates in some areas, BUT DD still states CF-2, straight weight in their 2-strokes.
Been using CF-2 in slow and fast boats. Oil samples are drawn often. Never a bad oil report.

I'm not meaning to argue with your comments, these modern oils MAY be better, but it's hard to argue or change from factory standards.
Don't think I've noticed a CH-4 or CI-4 in a single weight either.

Seems the Delo 400 stright weight (if it is still rated API CF-2) may have less of this ash than the Delo 100.
The Delo 100 is recommended for the 149s because of it's ash value (however it's counted). Both are considered good CF-2 oils around these parts.
I do use a different brand, not because of issues, just a better $ deal.
In the cold waters up thar, 30 wt may be perfect. In Florida, 40 wt.

Good thing I don't go to bed very early...
Read the Delo400 data sheet...
"Delo 400 monograde oils are not recommended for use in DDC two-stroke engines."

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=77118&docFormat=PDF

rcrapps... I was not specifically referring to the particular grade but just the generality of "C" grade oils... happened to grab the API statement on the CI-4+ oil.

Now the why... it is the two stroke Detroit's rings are directly exposed to the ports. Something that does not happen in a 4 stroke.

Now I really do not think it was the lack of ash... rating in this case: As would be the case in a run all the time engine in commercial use.

I think your issue is the viscosity issue... not the ash value.... which simply means the additive for the sliding friction burns and leave an ash... the more modern oils leave little ash but the additives are more expensive.

In your use of low hours per year... set around a lot... long time between constant running and off. What happens is the oil around the rings basically gets thicker... gums up if you will... and is less lubricative. I would never suggest a 40 wt in your application and 30 wt is likely not a good choice either. I would use the Delo 400+ 15-40w or the newer semisynthetic version or the LE version.

I wrote that post before you did the post on using 40 wt.