Water in engine

Okay guys,

I managed to build up the broken starter motor mount on my engine with my MIG welder and drill a 10mm hole all the way through. This allowed me to use a longer bolt in the second starter motor hole with a nut on top and get the flywheel and starter gear to engage correctly.
Unfortunately when I then tried it, the motor engaged and everything stopped turning. I decided I must have a liquid lock in the engine and removed all the spark plugs. The 3 cylinders on the port side look fine, the 3 cylinders on the starboard side had a load of water come out. I drained the engine and there is no water in the engine oil. I doubt the head gasket suddenly failed on all 3 cylinders, so I am wondering if a fault on the exhaust system could have water running inside the exhaust manifold back to the cylinder head and then pass the exhaust valves into the cylinders..
It seems odd to have water in all 3 cylinders.. I have no idea how the boat exhaust system works, there seems to be a 3 into 1 exhaust manifold then above that there is a large casting with cooling hoses bolted onto the manifold with an outlet that runs back to the prop.. I am going to look in the manual to see what the casting above the manifold contains and how it works..
Obviously water got into the cylinders when I stopped the engine, then when I tried to restart I got a liquid lock and the starter motor broke its casting due to the large force of trying to turn a locked engine. I am going to run a compression test (now that the starter motor works!) and see if the head gasket has gone or not, but thought I would ask you guys for any ideas as to what could cause water to suddenly appear in all 3 starboard cylinders.

Looks like a few late nights in the garage to get it running, but atleast the starter problem is cured and the new mount is definately strong enough!! It didn't break trying to turn a locked engine!! I am sure I can replace a head gasket with the engine in the boat, so I hope I have escaped removing the engine!!

Gary

Re: Water in engine

Well I ran a compression test and I think it proves that the head gasket is good. I cannot remember how you number the cylinders on a V6 so starting with the starboard side, going from the back of the boat to the front, I have 120 PSI, 150PSI, 150PSI, then on the port side going from the back to the front of the boat I have 150PSI, 120PSI, 150PSI. Two cylinders are a bit low, but I can live with that, it could just be lack of use. The amount of water coming out of the cylinders would require a significant break in the head gasket!! These pressures indicate to me that the head gasket is okay.. Do you agree? I am going to continue on my assumption that water is getting into the exhaust system and back into the engine via the exhaust valves..
I am still very open to any ideas or suggestions..

Gary

Re: Water in engine

Re: Water in engine

Depending on the kind of engine.. I know Volvo and OMC have exhast "flappers" in the exhust system.. and they burn up, or get stuck a lot. Maybe you have this type of problem, and water backup up on that side of the motor through the exhuast port.

Re: Water in engine

Follow Haut's advice before proceeding further. One bank full of water is a sure sign of trouble in the manifold or riser.

FWIW, if there is any question at all about the manifold or riser, replace it. If the set is over 10 years old, it's time to consider replacement anyway as a matter of preventative maintenance.

Re: Water in engine

KaGee said:

Follow Haut's advice before proceeding further. One bank full of water is a sure sign of trouble in the manifold or riser.

FWIW, if there is any question at all about the manifold or riser, replace it. If the set is over 10 years old, it's time to consider replacement anyway as a matter of preventative maintenance.

Click to expand...

Add to that if one side failed can the other be far behind??

Re: Water in engine

Well I unbolted the riser from the manifold and the gasket between the riser and the manifold has failed!! I sucked the water out of the manifold, changed the plugs and started it up briefly!! All 6 cylinders run!! I only ran it for 15 seconds (no cooling water) to check all was good. Hopefully a new gasket should cure the problem. I could not find a flapper valve in the exhaust but their could be one further down the exhaust system where it enters the stern drive, but I can't see down there. I will change the gasket that has obviously failed and see what happens. As there are no moving parts, why do you say to change the riser every 10 years? The engine was replaced 2 years ago, but I don't know if they also changed the risers, but they don't look like they are very old! All the paint is still on them and there was not much carbon inside..
I will change the same gasket on the other manifold to be safe..

Regards Gary

Re: Water in engine

A bad gasket will do that.

Manifolds and risers lifetime varies on the type of system you have and the type of water you boat in. Some guys only get 6 or 7 years out of a set. Others up to 20. The water jacket gets a hole from corrosion and away she goes.

If yours look OK, just keep a mental note of it.

Re: Water in engine

Re: Water in engine

And don't ever start your motor without water...even for 15 seconds!

I would now think about replacing the impellor.

Re: Water in engine

Thanks Guys,

I assume the impellor is inside the water pump? There was water in the cooling system, (I had not drained the system) but the stern drive was not in a water supply, so the impellor was not runing dry, it just wasn't getting a fresh supply of water.. I will still look at getting a new impellor as all sorts of rubbish probably get passed through the pump when the boat is in use, so it would be wise to change it. I got 2 new exhaust/riser gaskets for $20 so I will change them tonight.. As usual, because the boat will be ready for the lake, the weather is awfull!! The only time I get nice weather is when the boat is out of action!! Someone up there doesn't like me!!

Gary

Re: Water in engine

No - the impellor is different than the water pump.

Yes - you probably burned it up. It is in the lower unit. (Assuming you have a Mercruiser, Alpha)

Re: Water in engine

So how much of a job is it to change the impellor? I do have a Mercruiser alpha 1 stern drive! It seems the impellor is located in the bottom of the stern drive. Does the impellor turn all the time, or only when the propellor is turning? I ran the engine in neutral without the prop turning..
I could not see any gasket between the lower stern drive and the upper housing!! It looks like I would need a new impellor and oil for the staren drive? If there is no gasket, there must be some kind of sealant between the 2 parts, so what sealant do you recomend? Any special tools required to change the impellor?

Thanks Gary

Re: Water in engine

Gary,
Here is a link showing how to change the water pump in the outdrive:
http://mercstuff.com/waterpumpinst.htm

Re: Water in engine

Many thanks Fishermark.
Yet another question.. I looked up the service manual for my stern drive (My SELOC book was not very usefull!) and it seems that there is a butterfly valve in the exhaust to stop water coming back up the exhaust and into the engine. According to the diagram in the mercruiser manual this valve is only present on the port side exhaust.. I looked on my boat and the valve is present on the port side, but is missing on the starboard side!!
Now when I had water in my engine, it was the starboard bank of cylinders that had water in them.. I can see no logical reason to have the valve in only the left exhaust and its a bit of a coincedence that the side without the valve was the same side that had water in it!!
I think I am going to order a valve for the starboard side just to be safe (I can't see it doing any harm even if mercruiser didn't intend to have one).

Do any of you know if the alpha stern drive really does only have a non return valve in the port side exhaust, or is this a problem unique to my boat? I suspect this may have happened before and that's the reason the starter motor mount was originally broken!!
I also bought a new impellor and will change that over the weekend (bad weather forcasted here in Austin!).

Gary

Re: Water in engine

On another thread, Don says if you look down at quananties, it shows 2, port and starboard.

Re: Water in engine

Ayuh,...... There's Supposed to be a Flapper Valve in Each side of the Y-pipe........

And,......
Unless this Hydro-lock occurred because you Suddenly chopped the throttle,+ came to a Quick Stop,........
I'd be Replacing your Manifolds,+ Risers........

Re: Water in engine

The water lock did occur after a very rapid stop and cutting the engine.. There where also a lot of other boats around running at high speed so there was a lot of waves and wakes hitting my boat.. I will keep an eye on everything,but I am pretty sure there was a small leaki on the riser/manifold gasket and the lask of a stopper valve in the exhaust caused my problem.
Fingers crossed.

Gary