Can water get up to the air intake??

[Mattyb]

Please help guys

I spent the whole weekend putting in new engine mounts and disconnected the mixing elbow for better access. There was a trickle of water coming out over the 3 days it took to put the new mounts in which I thought was odd as I had the water through hull closed. Once I had put it all back together I fired her up and she ran perfectly and so much quieter than before. Everything was fine at this stage.

Today only 2 days later I was going to fire it up and put her in gear to see how the alignment looked but when I hit the start button she turned about half a revolution then it stopped but the starter was still trying to push. Felt then like a compression lock up. Tried a few more times but then the starter gave out and i got nothing out of it.

At this stage I was thinking starter motor, but when I took off the air intake cover there was a small amount of water in it pooled at the bottom, about half a teaspoon and the filter was a little wet.

There is no water in the oil, the batteries were fully charged and she ran like a dream on the last start. I am hoping its just the starter motor and the water is just some weird coincidence!! It is an older yanmar 2qm20. I also could turn her over by hand with the decompression levers on but not sure if this would make a difference. Is she stuffed or is there hope?????

[Kettlewell]

Don't try to turn it over until you make sure you don't have water in the cylinders--you could destroy the engine! You may be getting a water siphon that is filling up your muffler and then backing up into the engine. Not sure how that could happen if the seacock is definitely closed--are you sure it is closed? Sometimes seacock handles are reattached in the wrong direction making it look like it is closed when it is open. Or, did you have to do a lot of engine cranking to get the engine started? That can sometimes fill up the waterlift muffler and you get water backing up into the engine.

[Mattyb]

you could be right about the seacock and I will check but then it would surely have happened before then? She started no problems and has always started easily and ran beautifully.

[John A]

If you stop your engine while the RPM's are high you could set up a siphon condition that could over-whelm the anti-siphon valve on the riser. I've seen it happen

[Mark1977]

Originally Posted by Kettlewell

Don't try to turn it over until you make sure you don't have water in the cylinders--you could destroy the engine! You may be getting a water siphon that is filling up your muffler and then backing up into the engine. Not sure how that could happen if the seacock is definitely closed--are you sure it is closed? Sometimes seacock handles are reattached in the wrong direction making it look like it is closed when it is open. Or, did you have to do a lot of engine cranking to get the engine started? That can sometimes fill up the waterlift muffler and you get water backing up into the engine.

+1 You have water in the cylinders. You should get it out as fast as possible. This is exactly what happened to my motor and caused it to be seized up.

[Mattyb]

i just dont get how it got in there all of a sudden. hmm John i may have shut her down while the revs were still up as i only ran it for a short time to see if it was all ok. Looks like i need to take the head off. never done that before. Best be getting the manual out. Just need to figure out why this has happened in case something else needs replacing

[Kettlewell]

You can pull the injectors first to see if there really is water in there.

[msponer]

Or check the oil-- when mine flooded it was pretty obvious, since the oil was milky.

My previous engine flooded a handful of times (long story), but with immediate oil changes and plenty of babying it went on to last quite a while. The turbo eventually seized, but aside from that I think it would have gone on to lead a pretty normal engine life.

[Mattyb]

Kettlewell - The injectors are press fitted. I tried pulling them once but couldnt get them out. Might have to try harder.

msponer- there is nothing in the oil. Thats what has me thinking that somehow it hasnt gone through the pistons because to get all the way up to the air intake it would really take a heap of water.

I will try pulling the injectors then failing that just pull the head off.

[perchance]

Originally Posted by Mattyb

Kettlewell - The injectors are press fitted. I tried pulling them once but couldnt get them out. Might have to try harder.

msponer- there is nothing in the oil. Thats what has me thinking that somehow it hasnt gone through the pistons because to get all the way up to the air intake it would really take a heap of water.

I will try pulling the injectors then failing that just pull the head off.

At TDC the volume in the cylinder is quite small and a tablespoon of water may be enough to hydrolock the engine. The fact there is no evidence of water in the oil means you caught it in time.
Pulling the head at this point might be a bit premature.

[John A]

You should be able to remove the injecters as they are removed when you do a compression test.

I'd suggest removing the injectors ASAP and pour a little oil in the cylinders, then hold your thumb over the injecter hole while you crank the engine. Do this several times to flush the combustion chamber and lub the cylinder walls.

Good luck a saving your engine!

[Mattyb]

Perchance, lets hope so!.

John A - I tried doing a compression test a while ago, thats why I know I cant get them out. Well I couldnt get them out last time but I guess I will need to try harder this time.

Kettlewell - I just checked the seacock and it actually doesnt close all the way. The handle hits the side of the boat which leaves the seacock cracked by a few millimeters. Thats what would have caused the constant dribble whilst I had the exhaust elbow off for those few days. Maybe that has something to do with it. When the elbow is on it would create enough back pressure to stop the water coming in as I haven't ever noticed any water leaking out of the exhaust etc.

Ok so mission for tonight will be to try and get the injectors out and turn her over in theory the water should come out of the injector hole? Also there is a pre combustion chamber so not sure if this makes any difference?

[daddle]

Water in the oil will not turn it milky until the engine is run for a while.

The elbow dripping water out the engine end would be very worrisome.

I have found taking the head off sometimes easier than removing injectors. And it is far more informative.

The design should be changed so that a leaking seacock will not be a problem. Same for other situations like cranking for a minute or shutting down the engine from high RPM as mentioned above.

[daddle]

How would an open seacock cause a dribble of water? Some design problem there. Completely open seacocks should not cause a dribble at the elbow under any condition.

I have found it easier to remove the head that wrestle injectors out. And in this case it would be far more informative.

[Mattyb]

Hi Daddle

What I meant was that there was a dribble of water when I had the exhaust elbow removed. I removed it to have better access to my engine mounts. I have never had any issues with dribbling water when it is all together. But it shouldnt have dribbled even when the exhaust elbow was removed but this seems to be from the seacock not closing 100%