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Water in the cylinders

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captain_peter

Contributing Member
Weird but truth, omc 4.3 liter 1989 , I was out with the boat couple days ago and both engines ran good as normal
Anchored out and when it was time to return started one engine no problem when tried the other one didn't start at first second or third but started at fourth try, got back to our marina and after couple hours decided to try the same engine to see if this was a new problem since I never had problem starting the engines from the first or second crank.
This time it didn't even turn, I made sure it's not a battery or starter issue. Tried to turn the engine by hand and was almost impossible to turn. At the same time I heard some kind of water sounds running in the engine.
I took out all the plugs and they were all soaked. turned the key again engine cranked no problem but water was coming out of the back
spark plug holes.
What could be the cause, where should I start to diagnose ?
Your input is greatly appreciated.
Thanks
Peter
 
all 6 wet -might be the intake manifold rusted through it's cooling passage into the intake plenum
 
Peter... need more info!

Do you see milky engine oil?

Are these Raw Water Cooled, or fitted with Closed Cooling systems?

If CCS, and if you're not loosing coolant, then it's likely that you have compromised exhaust manifolds.
If raw water cooled, it could still be the exhaust manifolds... or it could be a crack within the engine block... but you'd likely see milky oil by now.

If you suspect the manifolds, you had better remove them and have them tested.

If at all possible (prior to removing the exhaust), remove the seawater pump supply to the engine, and do a 20 second low RPM dry start as to blow any water from the cylinders.
In 20 +/- seconds you will not create enough heat to cause any harm to anything.

This is necessary as to prevent any damage that may be caused from the water that may have found it's way into the area behind the piston rings.
You'll want to get this out ASAP.

You can repeat this as needed giving things some time for cool-down.


.
 
Hi Ricardo,
Thanks for your input,
This engine is fed through the stern drive pump and is raw water,
To-day I was at the boat and took both exhaust manifolds out and they where both wet where they mate with the engine ports.
I filled them up with water and ran water through them and seen no sign of leaks.
Now to prevent rusting on the cylinder walls I sprayed fogging oil and cranked the engine couple times and resprayed
I hope this is enough protection.
Now when you say to have the manifolds tested is that similar to what I have done or there is a different way.
By the way some one told me to check the flaps in the exhaust which I did and both are stock open.
Since all cylinders seem to had water inside is there possibility that water backed up into the cylinders
Thanks
Peter
 
Hi Hystat,
I tried to work from Seloc manual but is not much infor about this subject.
I am trying to understand your theory with the intake manifold. Gas goes through the intake manifold and how does water gets into the cylinders?
Thanks
Peter
 
................

captain_peter said:
To-day I was at the boat and took both exhaust manifolds out and they where both wet where they mate with the engine ports.
I filled them up with water and ran water through them and seen no sign of leaks.
These need to be warm and pressurized for testing.


Now to prevent rusting on the cylinder walls I sprayed fogging oil and cranked the engine couple times and resprayed
I hope this is enough protection.
Earlier I suggested that you run the engine prior to removing the exhaust manifolds.
If not, you may have trouble later on.


Now when you say to have the manifolds tested is that similar to what I have done or there is a different way.
See above.

By the way some one told me to check the flaps in the exhaust which I did and both are stock open.
Since all cylinders seem to had water inside is there possibility that water backed up into the cylinders
During a surge wave.... possiibly.

Peter
Click to expand...

captain_peter said:
I am trying to understand your theory with the intake manifold. Gas goes through the intake manifold
Only gasoline fuel/air vapors cross through the intake manifold runners.

and how does water gets into the cylinders?
There is a coolant cross over at the forward area of this manifold. If the manifold was breached in this area, coolant would enter the valley, not the cylinders directly.
Click to expand...
 
intake is water cooled - seawater passes through across the plenum from head to head.

I can't think what else would feed water to all 6 cyls simultaneously.

kinda has to be the intake. It's not the most common way they fail - they usually rot below the t-stat and dump water in the crankcase, but sometimes they'll rot or crack up higher between water and air plenums

you can pressure test your cooling system and follow the hissing.
red x's = remove the hoses from manifolds and clamp a 5/8" bolt or dowel in each end

green arrow = introduce air where water normally feeds in to your tstat housing from the outdrive- max 15 psi (crappy tire has a regulator in the air tools section for around $15 that works well)

You'll probably have a large volume of air coming up the carb which won't pinpoint the breach perfectly but will at least eliminate exhaust manifolds as a possibility and give you some peace of mind about taking the intake off. If the system holds pressure - go back to looking at exhaust.


searay.jpg
 
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hystat said:
intake is water cooled - seawater passes through across the plenum from head to head.

1.... I can't think what else would feed water to all 6 cyls simultaneously.
kinda has to be the intake. It's not the most common way they fail -
2.... they usually rot below the t-stat and dump water in the crankcase,
3.... but sometimes they'll rot or crack up higher between water and air plenums
Click to expand...

1.... Agree. There is only area where the coolant crosses over (it actually leaves the cylinder heads, and enters the intake manifold T stat area), and that is at the front area.
A gasket breach would allow coolant to enter the valley area only.

2... from there, it would dilute the engine oil causing oil hydrogenation.

3.... wouldn't that be rather rare?


Example only
634838=19034-SBC%20cooling-system%20rwc%202.jpg
 
I'm trying to recall where coolant goes- there's a heat passage under the fuel bowl on the 4V but can't recall if it's coolant or exhaust that crosses over there.
looks like coolant in this pic
If you take the carb off, you might see water running in or at least rust stains
43_19.JPG
 
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captain_peter said:
Hi Ricardo,
Thanks for your input,
This engine is fed through the stern drive pump and is raw water,
To-day I was at the boat and took both exhaust manifolds out and they where both wet where they mate with the engine ports.
I filled them up with water and ran water through them and seen no sign of leaks.
Now to prevent rusting on the cylinder walls I sprayed fogging oil and cranked the engine couple times and resprayed
I hope this is enough protection.
Now when you say to have the manifolds tested is that similar to what I have done or there is a different way.
By the way some one told me to check the flaps in the exhaust which I did and both are stock open.
Since all cylinders seem to had water inside is there possibility that water backed up into the cylinders
Thanks
Peter
Click to expand...

Ayuh,.... Are they the one piece manifolds, or manifolds, 'n risers,....

If they're the 1 piece, "Bat-wing" manifolds,... They're Junk,.... Yer lucky they didn't cost ya yer motors,...
 
Hi Hystat,
Thanks for the picture as they say it is worth a million words I will try the air test this weekend is simple enough, Let's see what the outcome will be.
You mentioned that air might come out of the carb. does that mean leaking into the intake manifold ( bad manifold ? )
 
I been at the boat and did the air test and I could hear very fine air leak that I was not even sure if it's coming from the engine or from the air hoses that I connected. So I decided to put every thing that I took out back and that includes new flaps in the Y exhaust to the out drive before putting the plugs back I also did a compression test and 4 outside cylinders read 175 and the two middle ones (3 + 4 ) 160
Couple cranks and it started and ran no problem, an hour later re tried again and started without hesitation.
While I was installing the exhaust manifold I had to remove the two hoses for the remote oil filter and by surprise the oil that came out of the hoses was very milky and so was the filter that I removed right after. So I pumped all the oil out and used three liters of fresh oil to flush out all the contaminated oil and refill right after with fresh oil.
The conclusion I came about that must been the frozen flaps in the exhaust Y
The next time I will be at the boat I will make a vacuum test to make sure there isn't anything else brewing.
In the mean time I like to thank all of you that offered your professional advise and took extra time to send those pictures, that really helped me.
Peter
 
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I was up at the boat, took it out for 1 hr. w/o throttle run and all gauges showed normal this the second time I done this.
Keeping my fingers closed it will keep running with no problems.
Thanks
 
captain_peter said:
Can you explain why they are a ticking bomb more than others.
Thanks
Click to expand...
mainly because the riser can't be inspected as it can with 2 pc. They were designed to last 10 years or so in fresh water. They usually last 20 in Ontario in my experience, but yours are 25.
I would budget for new ones.
 
Moore performance in California have a kit they ebay to go to center riser GLM's - about the only reasonable option I have seen. It's on the low end of quality but with some pre-install inspection and maybe light machining (Moore probably check them for you if requested), they would probably be fine in fresh water.

OSCO has a kit too which is better quality but probably double the money. marinemanifold.com out in BC can quote you on that.(maybe the GLM too)
 
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