Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

I have a 1996 Searay Bowrider with a 4.3L 6cyl 2 barrel Alpha GenII. I checked the oil on Friday, no water in oil. I ran the boat for about 2 hours on Saturday while fishing. Sunday morning I put in at the dock and ran for about 10 minutes when the engine started knocking and then completly shut down. I opened the engine cover and saw the mayo looking emulsion spewed all over the engine. About 1-2 gallons. Before I start tearing the engine down has anyone seen this? I know a bad head gasket could be the likely culprit as well as a hole or crack in the exhaust manifold. The reason I ask is if its a head gasket or manifold then I'll replace it myself, but if I'm barking up the wrong tree, then I'd rather find out from you guys that know, or if you have any other advice or other things I should check first.

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

as lame an answer this may sound like....
you won't know until you look closer. possibilities abound.... head gasket, cracked block, cracked head, manifolds.... anyhow... easiest perhaps to remove heads and look..... I am gonna bet on a head gasket cause it is an easy fix. also remember the sooner you get that water oil mix out of your engine the less corrosion will occur.

Sean

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

I hope you can tell, in a well lit marina, that it's an inboard, not an outboard.

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

The reason I ask is if its a head gasket or manifold then I'll replace it myself, but if I'm barking up the wrong tree,

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Ayuh,... The odds of it being a Headgasket are about Nil...
Cracked block, or maybe intake manifold are Much more likely...

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Have a look at this thread, I think it fits your problem to a tee.
http://forums.iboats.com/showthread.php?t=369864

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

either way he is going to have to make a choice... begin tearing into it to find the problem, or have someone else do it.... I really hope it isnt the block and that he gets off inexpensively. Someone must make that decision and move fwd with it or expect ever higher damages/expenses as it rusts more internally with ea passing day.

Sean

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Thanks guys. I was leaning toward the exhaust manifold because of the volume of emulsion. I didn't want to even think about the block being cracked (Trying to ignore the worst case scenario). Thanks for the input. I won't be able to tear it down till this weekend. I have heard some guys will use deisel fuel to displace the water in engine or to at least protect it some till repair can be made. Is this a good option to try and prevent some corrosion or is there something else I should use like mix oil and deisel to pickle it?

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Broken piston ring letting blow by in valve train.Seen it many times.

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

I was leaning toward the exhaust manifold because of the volume of emulsion.

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You will not get water into the oil through the manifold while the engine is running. Think about it. You have the exhaust pushing water out the exhaust, so how does the water from the manifold get to the oil pan ????? It can't. And that engine does not fill up with water just sitting there and not running.

Broken piston ring letting blow by in valve train.Seen it many times.

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How does that fill the oil pan full of water ????? Rings aren't hooked to a water hose and blow water into the pan when the engine is running does it?

Did anyone read the link I posted earlier, and look at the Merc service bulletin I linked to?
Here it is again.

http://forums.iboats.com/showthread.php?t=369864

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

i am with Don on this one - but what could have caused such a thing ????

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

boyoboy said:

but what could have caused such a thing ????

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Again, Read the link, it answers that question to. It got cold and wasn't properly winterized, froze, and cracked the block.

This is a typical start of the boat season post, happens every year, never fails.

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Don S said:

Again, Read the link, it answers that question to. It got cold and wasn't properly winterized, froze, and cracked the block.

This is a typical start of the boat season post, happens every year, never fails.

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I thought i was being sarcastic

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Don S.,

I think you are probably correct, I wasn't disputing that. I appreciate your input. The engine was winterized and kept in the garage but block could still be cracked. I'm going to have to tear the whole thing down anyway so why not check the exhaust manifold? The oil/water emulsion was so thick and so much of it that I knew it had been churned quite a bit. When the engine started knocking and then 30 seconds later shut down there was oil/emulsion blown out the back into the water from the exhaust as well as the top of the engine. I am just hoping that it was one of the manifolds but I will be able to tell once it is stripped. In theory it could be a combination of things. I'm just trying to learn more about marine engines and thank you for your expertise.

Re: Oil/Water Emulsion Spewing From Flame Arrestors and Valve Covers

Not sure what you mean j-martin?