Normal rust on 2011 Mercruiser?

[Dave.I]

I have a new to me 2011 boat with 3.0L Mercruiser. The boat was in salt a few times and supposedly cleaned very well each time, mostly fresh water. Everything checked out on the boat but I was cleaning the flame arrestor and moved the cooling line between the head and manifold. Found some serious rust in there and outside the head near the spark plugs (haven’t pulled anything mechanical yet). Is this pretty typical or did I just buy problems?

 

[dingbat]

There is no “cleaning” salt.

You have to neutralize by flushing with something like salt away after each use. Even then your fighting an uphill battle. It permeates everything, The wiring is the most venerable.

It’s not if, its when will iron oxide start to form

 

[alldodge]

Normal, will take a very long time for that to become an issue.

 

[dingbat]

I would be more concern about the “rust” around the spark plug. Looks like the “moisture” came from the spark plug

 

[Dave.I]

Thanks for the info. I pulled one of the plugs and got in there with the inspection camera. Clean inside as far as I could see. I’m just unsure what would cause that much corrosion on the outside of the head gasket without some sort of leak, either from the head itself or the cooling lines that run over top of it.

 

[dingbat]

I’m just unsure what would cause that much corrosion on the outside of the head gasket without some sort of leak, either from the head itself or the cooling lines that run over top of it.

That is rust…not corrosion. Huge difference.

 

[Searay205]

where do you live? Block cools at night, hot humid air condenses in the morning and engine sweats or get wet every day. That is a source of moisture. When I stored my boat outside in Houston one summer you would have thought someone squirted it with a garden hose every single day. Another reason for rust is poor coating when built.....

 

[crazy charlie]

Normal, will take a very long time for that to become an issue.

NOT normal...I have boated in salt water for over 30 years and have never had anywhere near that much rust anywhere on my motors.You need to find out where the water is coming from causing the rust.Charlie

 

[Searay205]

That is surface rust. I been boating in salt water for 35 years and seen more rust than that in 6 months.