water in the cyclinders

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hobbit

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<span style="color:blue"> </span> I ran my Yanmar 3GM30F today with a pressure hose connected to the raw water pump inlet. When I shut it down, I forgot to close the pressurized water supply, and after a while water came out of the air inlet! Clearly I filled up the exhaust pipe and backflooded the cylinders. "Fortunately" it was fresh water, but still I am afraid that I screwed up badly... /forums/images/graemlins/frown.gif

Would like advise on how to refurbish the engine myself, if possible. For instance, is it possible to blow most of the water out of the cylinders? Step-by-step guidelines would be highly appreciated.
 
Get all the water out, drain the oil,change oil filter and fill with new oil. Run engine.
If you do it toomorrow you should get away with it. I have used this on engines that have been in the oggin , but you must act quickly.
 
FOR CHRISTS SAKE MAKE SURE ALL WATER IS OUT OF THE CYLINDERS PROIR TO TURNING THE ENGINE OVER EVEN BY HAND.
IT WILL HYDRAULIC & BEND SOMETHING & REALLY SPOIL YOUR DAY. /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif
MODERN ENGINES DONT HAVE DE-COMPRESSORS SO BE CAREFULL
good luck
roger
 
Agree with others. Speed is of the essence. If it's possible to turn the engine over by hand DO SO, rather than use the starter motor. That way any water in the cylinders with be gently ejected and no mechanical damage should result.

Otherwise, follow boatbuilder's itinerary but allow the engine to run until it reaches operating temperature. Stop it, change the oil again and run for at least half an hour.

I don't believe you will have any long term problems, but get to work first thing tomorrow morning!!!
 
Sounds like you have to take out the injectors then turn it over. I'm glad I have an old Bukh with decomperssors and hand starting.
 
No, the injectors stay in, at least on my engine, but then I have a Bukh too!!!

If Hobbit can turn his engine over very slowly BY HAND, the water will be ejected gently via the exhaust valves and the injectors need not be removed. Granted it's harder to do without decompressors but it will work.

This is not that unusual a situation and seldom results in major problems provided the problem is addressed without delay. The engine must be allowed to run for a long time after the second oil change to make sure any remaining water droplets are driven off. Only heat can do that, hence the need for a long run.
 
This is a common problem, if you use a hose pipe. If you are ashore use a bucket of water to feed the pump with a short length of pickup hose. Then use the hosepipe to fill the bucket, when you turn off the engine the pump stops and no more water can flood the engine.
 
Re: water in the cylinders

This has not been my experience, and is the reason I would not attempt to do this using the starter motor, it MUST be done by hand if you can't decompress.

It is extremely unlikely (I've never come across it) that the valves will make a completely airtight seal. If you have owned or played with a hand-start diesel, you
will know that turning the flywheel gently allows air to slowly pass through the valve/seating interface. This happens even if the valves/seats are in perfect condition or have just been ground in and, of course, only applies to the cylinder that's on it's compression stroke.

I can assure hobbit that this will happen, but it is slow and if the injectors, in a non-decompressible engine, can be removed and REPLACED easily and quickly (before rust sets in and damages them) that is clearly a better solution.

I have done this operation for several people over the years (as I said earlier, it ain't uncommon!!) and it has always worked without any damage whatsoever, it is just slower.

Using the starter motor is a real no-no until the engine can be turned (relatively) easily by hand.

The only other, but again slower, way is to remove the rocker cover and manually hold the rockers down to decompress the relevant cylinder. This obviously works, but adds time/inconvenience to the operation.

In hobbit's case, I would try turning the engine to eject the water by hand. If that proves to difficult, then either manually decomprsee or remove the injectors - in that order.

Actually, all this advice is probably far too late, as I'd hope our friend hobbit has already long been working on his engine this morning!!!
 
Re: water in the cylinders

Thanks for all the suggestions. Am off to the yard now! Fortunately this engine has decompressors, so I guess I try first to lift them, turn the engine over by hand many times, change oil and oil filter and then try to start it.
Will gratefully follow the advise of the intake hose feeding from a bucket.
 
Re: water in the cylinders

AS long as the decompressors are open you can spin the engine on the starter. Once you are happy most of the water has gone, start the engine (may be difficult, but dont panic), and run for at least half an hour, by which time the heat will have evaprated off any remaining water.
 
Re: water in the cylinders

[ QUOTE ]
It is extremely unlikely (I've never come across it) that the valves will make a completely airtight seal. If you have owned or played with a hand-start diesel, you
will know that turning the flywheel gently allows air to slowly pass through the valve/seating interface.


[/ QUOTE ]
By the same token, water will flow around the piston rings, and push into the sump. If you use this method to eject water from the cylinders, it will be much better if you press something between the exhaust valve rocker abd the valve head to effect a decompression. Slowly turning the engine over by hand this way will a) prevent it starting as no compression b) prevent water being pushed past the inlet valves to be sucked back in on the very next induction stroke, c) prevent water pushing past the piston ring seals.
It is very important to dry out the cylinders quickly as has been said, as the bores will rust very quickly if permitted to become wet. So, in stages, pump all the water out of the bores as quickly as you can after getting them wet. Next, if there is any chance water has joined the engine oil, change that. If petrol, remove spark plugs and dry them out prior to replacing them. Diesel engine injectors should not need to be removed as the outlet pressure is so very much higher than the compression in the engine. Ensure you have removed whatever it was you used to open the exhaust valves for decompression pumping. Now, rotate the engine by hand slowly, and feel for any hint of a lockup. If all is well, you should now try to start the engine, and run it until warm through. Diesel engines are better run up against a load, so get it in gear against sound dock ropes and give it plenty of time!.
 
Re: water in the cylinders

[ QUOTE ]

The only other, but again slower, way is to remove the rocker cover and manually hold the rockers down to decompress the relevant cylinder. This obviously works, but adds time/inconvenience to the operation.


[/ QUOTE ]

Which is, f course, precisely what you said!! Teach me to read posts properly before jumping to conclusions!!
 
Re: water in the cylinders

Back home after a fruitful day in the engine compartment. I got the engine running again. Did exactly as was suggested, lifted the decompression levers, used a mole grip on the shaft pulley nut to hand-crack the engine many times, while spraying some WD40 in the inlet, changed the oil (did not look suspect as far as I could tell), undid and cleaned the electrical connections that had got wet from the water running out of the inlet, then cranked the engine using the starter motor (fortunately the electrics were still functioning, although I shall clean and protect them with contact spray again to avoid future electrical faults) and dropped the decompression levers one-by-one (3-cyl. engine). It took almost 30 seconds of hicking and puffing, but eventually the beast sprang back to life! As said, I left it running at 2000-2500 rpm for more than 30 minutes, to get nice and warm and dry. All's well that ends well....

BTW, I used the hose-in-the-bucket trick and found it worked well, however one must constantly keep an eye on the water level to avoid dry running or wet feet! Also, it provided an opportunity to measure the water consumption, which I estimated at 30 liters/min at cruising revs (2800 rpm). The Yanmar 3GM30F is an indirectly cooled 28 HP engine.

Thanks again for the tips! You've saved me a lot of agony (and money, probably)!
 
Re: water in the cylinders

Excellent result!! Congratulations, I'm very glad it all worked out for you. Thanks for coming back and letting us all know.
 
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