Water in 4.3 mercruiser.

[irishladdie]

Water in 4.3 mercruiser.
Hi all looking for a bit of help from all you old boating guys, i have been told that there is water in the engine of my boat, this is how it goes.
Had problems with engine and starter, lug broken on starter motor, engine not running correct.
took out of water, replaced a lot of parts, ie seals, bearings etc ( hard to know as what they call them here in Turkey is different from the USA/UK).
Tested back in the water, everything ok, go back to the UK for 2 weeks, had bad rain while i was away. Go down to the boat and try to start, turned over 3/4 times then click.
Thought it was the battery so charged up, back down and tried again, same thing.
Tried a couple of days later same thing, so got mechs to check, they took the starter off and tested ok, checked battery ok. They now tell me that there is water in the engine, coming in through the exhausts.
My question is if the boat has not been running, just sitting in the marina how can you get water into the engine, and even if there was water in it would it not still turn over??
I am no mechanic, but i would have though it still should have.
Is all this possible or am i being taking for a ride here in Turkey??
Hope there is one of you guys who have the knowledge regarding my prob?
Thanks

Len

[ss3964spd]

Hi Len,

Water should not be getting into the engine if the boat has just been sitting.

The symptom you described; tried to start the engine, it turned 3/4 or so then stopped, sounds a LOT like there is water in at least one cylinder. If you tried to start it again and the only thing you heard was a "clunk" from the starter, that's another symptom of water in a cylinder.

If they are saying water is getting into the engine the first thing to do is remove the spark plugs and see if any water comes out of the spark plug holes. If water does come out then it's confirmed. If it is water in the engine you'll have to start inspecting the exhaust system (manifolds and risers). Only real way to do that it to take them apart.

Dan

[irishladdie]

Hi Dan,
Thanks for your reply. They have taken the engine out today and stripped it down it, you can see very clearly that water has got in, they sent me photos of it and i must say i am quite shocked by them.
Perhaps you could explain to me how the water can get into the exhaust sytem?
In Oct they had to remove the engine and outdrive as there were problems with the flywheel and starter, this was when they fitted new seals,. bearing etc If these were not replace correctly is it possible that this might be the cause, allowing water in??.
I have not been able to speak yet to the agent re what they can do with the engine, do you know it it can be repaired ok, will it require a lot of new parts etc??
Thanks,

Len.

[ss3964spd]

Len,

Yes, water can get into the exhaust - and then the engine. Remember that the exhaust manifolds and risers have water flowing through them and if the exhaust system is not put together correctly, using the correct gaskets and seals, water will get into the engine.


Almost anything can be fixed but since I cannot see it with my own eyes I have no idea how much damage there is. You're best bet is to find a licensed Mercury Marine mechanic - someone who knows (or is supposed to know) what they are doing.

Dan

[Argonaut]

Do you have the carb version ? ............ if so there is a very well known issue that the engine suffers form dieseling when hot, this can cause the engine to run in reverse, sucking water into the cylinders. If that happens - VERY expensive.
There is a Tech Note from Mercrusier on this .. I can let you have a copy if you want it (easy to Google for I should guess)

In simple terms on an mpi engine when you switch off no fuel can get into cylinders.
On carb engines, when you switch off the inlet ports can have some glowing particles of carbon ... this ignites fuel without spark, and as it turn crank it sucks in more fuel as carb syatem is still fully functional even though ignition may be off.

Several simple fixes for this (all it Tech note)

All of this is of no use if you have an MPI engine.

[dubble dippin]

You probably have this sorted out already but I had the same experience. I bought a boat which was trucked to my home but the boat was not covered at the time. During transit there were heavy rains. When I launched the boat the 1st engine started right up but when I went to start the 2nd I got the unfamiliar "clunk". My 1st instinct was water in the cylinders. I took out the plugs and turned the engine over and sure enough out comes water. My boat sits in salt water, so having spent 30 years in the Navy the 1st thing I did was taste the water. Thankfully it was freshh water. Once I cleared all the water out of the cylinders and dried and re-installed the plugs I started her up and haven't had a problem since (2 years ago). The problem was that during the heavy rains during transport water flowed into the Engine compartment onto the shield that covers the anti-flash filter, down through the securing bolt that secures the cover and filter right into the carburator. My fix was to repair (seal) the cover (it was cracked) over the anti-flash filter and ensure that whenever heavy rains are forecasted I double check both engine carb covers as well the canvas. So far I have not had an issue. Just my two cents worth

[millman28]

My 4.3 does the same thing with the dieseling. I just let it idle for a bit before shutting down and haven't had a problem since.

[Argonaut]

If you take a look at Tech note - it's fixable.
Put in the alternative plugs they advise and set timing as descibed.
Worth giving a copy of Tech note to whoever does your servicing.