Water in Cylinders

[hsvengr]

2006 Mariah SX19, 4.3L V6 Mercruiser.

What would cause water to collect in the back two cylinders on the left side of the engine after sitting overnight? The water causes a "hydro-lock" preventing starting. The engine just goes "click"; then nothing. The engine can be started by removing sparkplugs, starting on 4 cylinders, putting plugs back in, then it runs normally. Turn it off, let it sit overnight, then there's water in the cylinders.

The intake manifold was replaced after freezing cracked it. The head was magnafluxed -- no cracks. The exhaust manifolds hold pressure -- so, do not seem to be cracked. It is not rainwater thru the carb -- the flame arrestor is in place and the engine has been covered.

Any ideas why this water is collecting in the cylinders? Thanks.

 

[Bt Doctur]

Re: Water in Cylinders

heads , manifold or riser is leaking.
"The intake manifold was replaced after freezing cracked it."
That answers it all.

 

[hsvengr]

Re: Water in Cylinders

I would agree with you, Bt Doctur, that the intake manifold being cracked would be the problem of water in the cylinders, but it's been replaced. Why would water still be collecting there? Also, would you explain what you mean by "riser"? Thanks.

 

[TilliamWe]

Re: Water in Cylinders

Exhaust manifolds or risers. They are the one 1 reason (and the number 2, 3, and 4) for water in an engine. If you don't know what a riser is, It's the piece that rises off the exhaust manifold and directs the exhaust towards the back of the boat.

 

[Simoniz]

Re: Water in Cylinders

If the exhaust manifolds are pressure tight, how about the risers? They (and the manifolds) have probably also been damaged by frost.

If the gasket between the exhaust manifold and the riser is leaking between the water jacket and the gas path (inside of riser/manifold), then water will leak in from the riser, run down the inside of the ex manifold and into the cylinders.

 

[Turn-n-Burn]

Re: Water in Cylinders

or......

it could be a bad head/intake manifold gasket.......pressure test the engine block first.

 

[hsvengr]

Re: Water in Cylinders

Thanks, folks, for your suggestions as to possible causes. Turns out to be a cracked cylinder. Long block replacement now on order.
Sigh...

 

[Bt Doctur]

Re: Water in Cylinders

My quote was meant to say that if the intake suffered damage, other parts of the motor may have suffered the same fate. There is no reason to suffer from cracks IF the winterizing process is done correctly and on time. Seen a new rebuilt motor crack in 31 degree air because he thought it wasnt that cold. Guess what, it was just cold enough.

 

[hsvengr]

Re: Water in Cylinders

Yes, I agree that winterizing is really important. I had this engine winterized but only by undoing the 5 blue drain caps and fogging the carb trying to stall out the engine. (It never did stall -- had to shut it off.) But the boat was stored on the trailer, outside, and a bit nose up and that seems to have been what cracked the intake manifold. The mechanic tells me there is a recess that holds water if the boat is nose up. He recommends an antifreeze type winterizing process.

As for the cracked cylinder -- I don't know. Was that due to freezing? You would think that draining those 5 blue caps would take care of that.

 

[RogersJetboat454]

Re: Water in Cylinders

As for the cracked cylinder -- I don't know. Was that due to freezing? You would think that draining those 5 blue caps would take care of that.

Not if there was sand/rust/junk blocking all of the water from exiting out of those caps. It's a good idea to run a coat hanger wire in the drains to be sure any aforementioned blockages have been cleared. An opened drain that gushes water out is good. A drain that drips/dribbles water out is no good.

 

[TilliamWe]

Re: Water in Cylinders

... The mechanic tells me there is a recess that holds water if the boat is nose up. He recommends an antifreeze type winterizing process.

As for the cracked cylinder -- I don't know. Was that due to freezing? You would think that draining those 5 blue caps would take care of that.

The only "recess is in the back of the boat, down by the drain plug. That's why you store them bow up. No "recess" in the engine.

And as said, you always ream out the drain holes when draining. Then antifreeze is not necessary.