Water Ingress in to engine

[Gazjen]

Hi All

I've got sea water in two of my cylinders on the same side (V6) which has caused it to siez whats the most likley cause of this I've posted on the mercruiser forum but nobodys taking, I don't want to repair the engine and have it happen again

The head gasket seemed fine when I removed the head, can it go back down the exhaust in to the engine?

Thanks

[mr3dman]

You didn't mention the year of the boat or what conditions you boat in but yes you can get water in the engine through the exhaust. Here are a few senarios. first is salt water use and the boat exhaust is 5 years old or older. Sea water always corrodes the internals of the exhaust and will leak into the engine. second senario is having alot of people while at anchor and manage to get the swim platform low enough for the water line to get above your risers on the engine. and third would be having the rubber flappers in the exhaust burn out and taking a large wave at the stern at idle or engine off. Hope this helps

[seapuppy]

good post there 3dman....welcome to the zoo...yep...most likely the flapper valves are shot though....
when I'm on plane...and coming down to a stop or idle...I slowly come off plane...I try not to slam the throttle down to idle so that water doesn't wash back into the exhaust.....

let us know what you find out...

SP..

[Gazjen]

Hi

Thanks for the reply its a 96 but I brought the boat siezed so don't know how it happened the flapper valves look fine

I will take the exhaust manifold apart and have a look inside then

Would the water go in if it was overfilled when it was winterized?

[mr3dman]

only if the exhaust riser/ manifold was corroded, or the riser gasket failed. Basically the same senario as running the engine at sea or on a hose. My guess is corrosion

[markwebb2161]

I am a new owner of a 1993 Maxum 2700 SCR which had similar problems of water in the engine, there were several problems with my engine, here is a list of what you might check..bizzarly enough, my engine was running perfectly and only noticed the water when checking the oil....I would caution you to look farther than internal engine component failure, There are several components on the engine that can corrode to the point of actual holes in the exterior casing that will allow water into the engine, including as far as freeze plugs

1) Exhaust manifolds (to really check, they must be pressure tested)
2) any holes in the oil pump/cooler case
3) anywhere that would allow oil to mix with water, oil pan gasket ??

Some of these might seem odd, but remember that oil is heavier and will always sink back to the bottom of the engine, once water has infiltrated the engine, traces of it can be found as high as the oil filler cap.

I have just had the engine removed and am performing the following work.

Heads R and R'd
New oil pump, water pump, thermostat/impeller housing, exhaust manifolds are being acid washed, double roller timing chain, new timing chain cover, oil cooler....and installing a fresh water cooling system

Salt water is NOT a boaters friend under ANY circumstances, and extreme care and maintenance will become your best friend. I am lucky to be able to remove my boat from the salt water environment occasionally and cant imagine how the boaters who cant deal with the abrasive conditions...

Hope some of this helps

[Gazjen]

Thanks for the reply

My oil was quite clean, I don't think it's mixed with the water at all

I'm going to strip the exhaust manifolds and have a look finally got the seized pistons (2off) out today had to really thrash one of them out and unfortunately its damaged the piston. I'm looking in to the rebuilt engines on ebay at the moment. Think it will cheaper in the long run instead of trying to rebuild mine

Got some pics of the pistons if anyone's interested