water in the spark plugs

[swa737]

I have a mercruiser with a 5.7 lt 250hp alpha 1 outdrive. I pulled the plugs on both sides and there was water in the cylinders at least one on both sides. I need help determining where it's coming from either the head gasket, cracked block or maybe crank seals. engine has about 200 hours and does not overheat. It does hydro lock and won't crank until you pull the plugs.

 

[Bt Doctur]

Re: water in the spark plugs

in what cylinder numbers?
2,4 or 3,5 might indicate a leaking riser
or cracked exaust manifold.

 

[Don S]

Re: water in the spark plugs

Block off the water going to the exhaust and pressure check the engine block and see if it will hold pressure. (drain the water first)
If it holds pressure, chances are the manifolds, risers, or gasket between them is bad.

 

[TilliamWe]

Re: water in the spark plugs

swa, the #1 source of water in the cylinders of a marine engine is the exahust manifolds. The #2 reason is the exhaust manifolds. The #3 reason is the exhaust manifolds. The #4 reason is the exhaust risers. The number #5 reason is the riser to manifold gasket. Head gaskets, and cracked block are not real high on the list. Unless you know for certain the engine has gotten Very hot or froze over the winter.

 

[flabum]

Re: water in the spark plugs

swa, the #1 source of water in the cylinders of a marine engine is the exahust manifolds. The #2 reason is the exhaust manifolds. The #3 reason is the exhaust manifolds. The #4 reason is the exhaust risers. The number #5 reason is the riser to manifold gasket. Head gaskets, and cracked block are not real high on the list. Unless you know for certain the engine has gotten Very hot or froze over the winter.

You got it backwards..... #1 cause is the risers, #2 is the riser gaskets and #3 is the maniflods

 

[swa737]

Re: water in the spark plugs

Water is in all cylinders for sure. What should I look for in the riser. Can you test them.

 

[flabum]

Re: water in the spark plugs

What year is the engine?

How do you launch the boat?

 

[swa737]

Re: water in the spark plugs

2001 trailer launch.

 

[TilliamWe]

Re: water in the spark plugs

You got it backwards..... #1 cause is the risers, #2 is the riser gaskets and #3 is the maniflods

Ha ha, you're real funny, bum. My point is and was, guys who aren't used to marine engines always end up looking at head gaskets and that's just not the first thing to check. It's so much easier to check risers and manifolds.
(BTW, when you have stainless steel risers like I do, it's the manifolds first, gasket second. If it's the riser, yikes!)
Remove the riser, it may be obvious that there is a problem. Meaning they'll be so rusty, it'll be obvious they are junk.

 

[TilliamWe]

Re: water in the spark plugs

Could be a "flapper" issue as well, couldn't it?

 

[oops!]

Re: water in the spark plugs

on my inline 6 it was the manifolds.
in my inline 4 it was the manifolds.
im getting real good at pulling manifolds.

if you do what stickey says. youll find the leak.

 

[flabum]

Re: water in the spark plugs

Ha ha, you're real funny, bum. My point is and was, guys who aren't used to marine engines always end up looking at head gaskets and that's just not the first thing to check. It's so much easier to check risers and manifolds.
(BTW, when you have stainless steel risers like I do, it's the manifolds first, gasket second. If it's the riser, yikes!)
Remove the riser, it may be obvious that there is a problem. Meaning they'll be so rusty, it'll be obvious they are junk.

Actually, I have seen the stainless risers fail faster than the iron ones. The stainless ones tend to crack and the tuned stainless ones, like the Gil's, will leak at the welds from electrolosis.

But we are right..... maniflolds and risers will go first.

I ased how he lauches his boat because if he has a steep ramp, he could be dunking the engine while backing it in. Seen that too many times.

 

[TilliamWe]

Re: water in the spark plugs

Yep, a too steep, too fast back down on the trailer, with bad exhaust shutters would allow water in the cylinders also.

 

[Bondo]

Re: water in the spark plugs

What should I look for in the riser.

Ayuh,....
You're looking for a Perfectly Flat gasket sealing surface,..... A Prefect Gasket Seal,+ No Crud or Chunks of debris in the little Outlet holes on the exhaust side.....

Bad Gasket Sealing Surface on either the Riser or the manifold will allow a Leak.....
The Crud,+ Chunks in the Outlet Holes will cause Overheating,+ might mean the inside walls are crumbling apart.....

Can you test them.

Nope,.......
But the Manifolds,+ Block can be Pressure Tested......

 

[krisnowicki]

Re: water in the spark plugs

I had the same problem and it was the riser gaskets on both sides... happens... but folks here helped me figure it out

 

[krisnowicki]

Re: water in the spark plugs

have you over heated recently...

 

[swa737]

Re: water in the spark plugs

Never has overheated, ran great, out fishing, went to restart and it was hydrolocked, would not turn over. I pulled the risers and exhaust manifolds, the only obvious sign is slightly deteriorated gaskets at the risers, this may have happened during disassembly. Engine is a 2001 with 170 gentle hours. Is the flapper a single one for the entire exhaust or one for each pipe.

 

[Bondo]

Re: water in the spark plugs

Is the flapper a single one for the entire exhaust or one for each pipe.

Ayuh,.....

There should be 1 set in each side at the Top of the Y-Pipe.......

 

[Don S]

Re: water in the spark plugs

Did the engine diesel when you shut it down? That can suck water back into the cylinders thru the exhaust.

 

[swa737]

Re: water in the spark plugs

Thank you guys so much for all the info, new gaskets on order and will investigate flappers this week. Thank God for Al Gore's internet.: