4.3 LX Water in all cylinders

[dadcoy]

1994 Mercruiser 4.3 LX was running normally at high idle. When accelerated to mid-throttle it coughed, ran rough then quit. Water in all cylinders. No obvious external leaks. Can't believe both head gaskets or manifolds blew simultaneously. Is there a common water source that could have filled the intake manifold? Leak in thermostat housing? Original owner, no salt water, has been running great all summer. Now a bummer.

 

[1ruralmailman]

Re: 4.3 LX Water in all cylinders

4.3 are known for cracking an intake manifold.they have a cross over for water in them.that said is hard to believe you would drown all cylinders n one fell swoop,without some warning.

 

[MPII]

Re: 4.3 LX Water in all cylinders

Seems really hard to believe that you would loose the entire gasket all at once. Is this the first summary for it? Was it properly winterized? 4.3 Mercs can get water in through the exhaust manifolds. There is actually a service bulletin on it, goole Mercruiser manual #7 service bulleting on exhaust manifolds. What happens is that water gets in and sits on top of the valves and as they open, they drop water in. Still, wierd that it would be ALL of them.

You're going to have to do a "leak down test" to check each cylinder for the head. It's pretty tricky becuase you need to make sure that when you test, the piston is at top dead center.

Intake manifold can crack as was indicated. That would be more likely than the head gasket when you are getting water in all of them. A leak down won't diagnose a cracked intake.

Yea, that's a real bummer. Sorry to hear about your luck.

 

[Alpheus]

Re: 4.3 LX Water in all cylinders

4.3 are known for cracking an intake manifold.they have a cross over for water in them.

So does every other V- whatever engine. If the intake blew its gaskets you would have water in the oil. Do you???

What procedure did you use to find water in every cylinder?

What were you doing immediately before your engine quit.

Were you sitting in the water for awhile?

Were you picking up a skier/tuber and came to a sudden stop?

Just tell the story in your own words of what happened just prior to the engine messing up???

 

[Lyle29464]

Re: 4.3 LX Water in all cylinders

I would treat it as if it dieseled before I started taking things apart.

 

[thumpar]

Re: 4.3 LX Water in all cylinders

Like others asked, how do you know there is water in all cylinders and how does the oil look?

 

[striker3636]

Re: 4.3 LX Water in all cylinders

Take a look at my post here....
http://forums.iboats.com/showthread.php?t=431776
Exact same thing happened. Put it all back together with new fuel/water seperator and new plugs and runs perfectly. I believe its just a very occasional fluke with these motors that lets them act like a pump and suck water back in when. I've had my boat over 5 years and this is a first in many hundreds of hours of operation. Mines a '96.

 

[dadcoy]

Re: 4.3 LX Water in all cylinders

Thanks to everyone. The engine was running normally the previous week for several hours, tubing and skiing. No problems.

No water in the oil.

The water in the cylinders was diagnosed by removing the plugs, tapping them in the palm of my hand, and seeing the water bead up on my greasy fingers.

Before the engine quit we had been cruising slowly at about 1000 rpm for 10 minutes. When the throttle was opened to accelerate, the rpm climbed to about 3000, but sputtered, then slowed and died, all in about 10 seconds.

 

[sport2246]

Re: 4.3 LX Water in all cylinders

You have most likely suck up water thru the exhouset system. check floper valve if it is burnd or cracked. Just bought a boat from a guy that suck up water the way. Check dip stick if it has more oil then normal if so you have water in the pan. Drain right of way pull intake, heads and clean soon as possible otherwise cylinder bores with start to rust. You can save it if you do it ASAP

sport