Salt in cylinders

[masonc]

MY 33 ft CheoyLee has a Yanmar 3GM30F diesel engine. When we were wrapping up and motoring into harbour for haul out, the mixing elbow blew out. I had already ordered the replacement, so it was not a big surprise.
It was a few days before I was able to work on the boat in the yard. The engine was not able to turn over on the starter. I determined some water was ingested by the engine through the intake. I sprayed WD40 into the intake and opened the decompression levers on the three cylinders.
I put a 3/4" drive socket on the crankshaft and rocked the engine back and forward. I was able to get a few degrees of movement so I backed it up and tried the starter. Engine turned over fine. I removed the rocker cover and checked all the valves were opening and closing. The rocker area was very clean, no sludge, good to note.
I dropped the compression levers one by one and started the engine after a few attempts, and idled it for a few minutes, then changed the oil.
So the engine is fine. I will not be using the boat until after hurricane season. Can I get recommendations one how best to leave the engine. An experienced friend recommended squirting oil into the cylinders to ensure the residual salt does not freeze the rings to the cylinders again. Any thoughts on that?

[a64pilot]

I believe your friend is correct since you have decompression levers that means you can open them on recommissioning and prevent a hydro lock.
What happens with a little rust on the cylinders is it gets cleaned off when the engine is started, this will end up with polished bores, no cross hatching to hold oil, this will mean high blow by, oil getting very dirty fast and high oil temps and possibly even lower power and hard starting, only cure is to disassemble engine, home the cylinders and start over.
You may even look for some fogging oil which is specifically made just for this, fogging the cylinders with oil on an engine that will be placed in storage.
Sta- Bil is one manufacturer, less than $10 for a can, cheap insurance


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[masonc]

Fogging oil - Yes, that was what I was looking for. Great tip.

[a64pilot]

You have decompression levers, a great thing in my opinion, wish I had them. One thing they are good for in my opinion is for an engine that hasn't been run in a long time, you can pull the levers and motor the engine over and let oil circulate through everything before it has to go the stress of compression and starting, those of us without them can't.


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[masonc]

Yes, i love having decompression. Excellent for troubleshooting and winterizing.

[Lepke]

I use fogging oil in diesels for long layup. The engine will run on the oil so it has to be done with the engine stopped. Usually I remove the injectors. I usually fog, rotate and fog again. On startup, you get lots of smoke.

[boatbod]

In my opinion you want to run the engine hard, under load, for 30 mins or more before you lay it up. That way you eliminate any residual moisture before it can sit for months rusting away.

3GM series are sensitive to bending rods if attempting to crank a water filled cylinder. It may still run afterwards, but if you notice hard starting it's probably due to inadequate compression (should be over 400psi).

[masonc]

I can't run it hard, it was running it hard the blew out the elbow so now the boat is hauled. I would love to take it out and run it, once I get the new elbow installed and hurricane season is over.
I turned the engine over for a while with the compression levers open to make sure there was no water in the cylinders for exactly that reason. I also sprayed WD40 into the intake as it was cranking to help dispel any residual water. I didn't start it for about an hour so it would gets lots of time to spread the WD40 around, and there was diesel injected into the cylinders as it was being turned over. It ran for about ten minutes on idle before the elbow broke again, it was only fixed with epoxy.
I'll have the new elbow shortly and can run it for an hour or so to help keep it clear.

[Lepke]

When I was younger I repaired a number of diesels that had salt water flooding. If they were cold when flooded, and submerged briefly,the residual oil/fuel protected the cylinder/sleeves and related parts. Not all cylinders flood and the ones that did still had an oily film on the rings.
After awhile I quit disassembling and just ran with a couple oil changes. Those that came back for overhaul had the right number of hours. My opinion is that salt water doesn't have a residual effect with a good maintenance program.
If the engine goes under while running, it's usually better to get another engine because of temperature shock and hydro lock.