Water out the air cleaner!!

[svstrider]

I planned to flush my overheating Yanmar 3GM30 raw water cooled engines with Rydlyme descaler on my cat. I set up a circuit from the water pump">raw water pump and out the exhaust. I had already T pieced a fresh water flush using a bucket rather than attaching a garden hose.

I THOUGHT that as the descaling would happen without the engine running there was no danger that I would flood the cylinders. Using a pump to recirculate the descaler is the instructions.

To my horror, I saw water coming out the air cleaner after I tried my circuit before using the expensive descaler! On top of all this, I had replaced the gaskets on the exhaust manifold, cooling jacket & injection elbow. The latter also leaked despite my really tightening the bolts. = a total C...... F...

Advice please

I guess I have to remove the injectors and turn the engine over to get the water out of the cylinders. Shouldn't the elbow gasket have worked or does it need a hot engine to seal?

I could have just descaled from a hose end in a bucket using my T piece before the water filter but I thought that this closed system would have become too hot running for 2 hours as per the Rydlyme directions.

Time to call the REAL mechanics. Unfortunately, I have to leave town to work for 10 days and mechaics are not on call for stupid boat owners.

[four winds]

Sorry to hear this. With fresh water you haven't hurt anything yet in my opinion.

You can use the decompression levers to evacuate water also. But I would turn it by hand several times before using the starter.

With the engine off there was no exhaust pressure to help insure water didn't backflow in to the manifold and through an open exhaust valve.

Probably not water in all cylinders.

You can fix this.

[four winds]

Reading your post again, I must say I haven't heard of descaling and engine without it running. Not saying it can't be done.

Others will have good advice.

Maybe there is an issue at the fitting where water enters the manifold that is causing a diversion into the exhaust only side.

Maybe there is an issue with your gasket installation beyond the external leak.

[Lepke]

It's better hot, but not above 180°F. If you use the stock pump, run a hose to the sw pump inlet to a bucket. Run another hose from where the exhaust manifold water would normally go into the mixing elbow. Plug the elbow so exhaust doesn't come into the engine room. Fill the bucket with Rydlyme solution and run engine at idle.
I usually bypass the stock sw pump and use a bilge pump in the bucket and run for a few hours (w/o engine running) or until the Rydlyme is exhausted. A piece of sea shell in the bucket will bubble if the Rydlyme is still working.
As to the flooded engine. Either with compression release or removing injector, rotate engine back and forth until all apparent water is gone and engine can be jacked completely 360°. Start the engine and the water will be turned to steam and exhausted.
Attached is a clip of Rydlyme instructions. Original was too big.

[RaymondR]

Check the dip stick to see if any leaked down past the piston rings and if so change the oil before you run the engine. It happened because there was no exhaust gas to blow the water uphill to the exhaust overboard and it flowed back through the open valves in the engine. On a 3GM30 cranking the engine with all the valves lifted is usually sufficient to clear the water provided the battery is good and the engine cranks fairly fast.

[jamhass]

I would treat this like any other water incursion.

Best to 1) drain the water, 2) backflush cylinders with a solvent and oil to remove remaining water and caustic, 3) drain and change engine oil, 4) run briefly and rechange oil and filter.

Don't forget, the descaler is caustic and will likely lead to corrosion if left in the cylinders, so do not put this off, especially for 10 days. If you can't get a mechanic or DIY, promise a good buddy whatever it takes to do it for you.

[four winds]

Luckily, I believe the OP was using fresh water only to test his setup when this occurred.

So no descaler present yet in the engine.

[michaelratinter]

If you don't have decompression lever you might put pennies between tappets and exhaust valve stems to keep the valves open while you turn the engine over by hand.

[SV Bacchus]

Originally Posted by michaelratinter

If you don't have decompression lever you might put pennies between tappets and exhaust valve stems to keep the valves open while you turn the engine over by hand.

I'm not a mechanic so I'm just asking.. I've heard the clearances can be so tight on a Diesel, i.e. small combustion chamber at piston TDC to get the required very high compression, that it might cause the piston to contact the valve? Have you done this safely?

Again, just asking as this seems interesting if it would work.

[michaelratinter]

Bachus, yes I have done this in diesel repair class on a Yanmar engine. Instructor said it will also work on my Perkins 4.236.

[a64pilot]

Originally Posted by michaelratinter

If you don't have decompression lever you might put pennies between tappets and exhaust valve stems to keep the valves open while you turn the engine over by hand.

That is an interesting thought, but my luck the Pistons would tag the valves bending them.
Pulling the injectors is easy and much safer.

I'd first pull the injectors
Spin her over by hand and put some oil in the cylinders, spin by hand a few times and then use the starter, put a rag over the injectors holes to catch the water and oil slurry, you will be surprised how far it can be shot if you don't.
Then put injectors back in and run it a few minutes, change the oil even if it's not milky, then run it five min until hot, any evidence of milky at all, change it, repeat until oil is clear.
Cylinder walls will form a layer of rust amazingly fast, even with fresh water, there is a time limit, you need to get oil in there fast and stop the rust. The rust will be cleaned off by the rings very quickly, but it can lead to bore polishing as it may wear away the crosshatching, it's job is to hold oil for both compression and lubrication, crosshatch wears off, engine has a lot of blow by, oil gets filthy fast, oil temps run high and engine consumes oil.
Only fix is to disassemble engine and hone the cylinders.


Sent from my iPad Pro using Cruisers Sailing Forum

[SV Bacchus]

Originally Posted by michaelratinter

Bachus, yes I have done this in diesel repair class on a Yanmar engine. Instructor said it will also work on my Perkins 4.236.

Excellent, good to know!

[four winds]

But you do have decompression levers. Three levers on the side of the valve cover designed to hold the exhaust valves open.

No disassembly needed. And no chance of dropping the little stem caps into the engine trying to put pennies on top of them.