Flushing an Engine?

[Condor1970]

I came to an interesting conclusion yesturday when I pulled the exhaust elbow off my Merc 3.0L engine. It has 3 little water ports, and they all have some fouling around the edges, etc. My conclusion, since I know the original owner ran this boat in sea water, is that the whole engine, though still cooling as it should, probably has a lot of salt and fouling inside the coolant channels. Maybe even a little crusty marine growth. I started thinking about the possibility of installing a closed coolant system down the road if we decide to keep this boat.

What do you think would be the best way to flush out all that crud?

Without going through some special process with special chemicals, would simply hooking up a coolant system, and allowing the glycol to break everything down over time with regular flushes be the best route?

 

[achris]

If the engine is more than 12 months or 20 hours, forget about closed cooling, it'll cause more problems than it solves. What happens is the rust starts flaking off the internals of the water passages and end up clogging the heat exchanger.

As for flushing, quite a lot of people use salt-away... Personally, I use a special chemical, H[SUB]2[/SUB]O... Used in sufficient quantity it will flush the vast majority of salt out. I've had my engine since 2006, have over 350 hours on it (not nearly enough!) and have only ever flushed with fresh water. Due to some 'issues' with Mercury Marine I have a lot of opportunities to look inside the water jackets on a regular basis :facepalm:... Still nice and clean..

Chris..........

 

[Condor1970]

You know, that's kind of what the old owner told me in more simplistic terms when I bought it, and enquired about adding a cooling system.

He said, "If it it ain't broke, don't break it!"

I'm thinking I may just relegate the boat to mainly lake use for the first year, just to make sure it gets nice and clean.

 

[Fishermark]

I boat exclusively in salt water - and like Chris - simply flush the engine with water (on muffs) after use. You will need to keep an eye on your temp and check / replace the manifold and elbow when the passages get clogged and / or thin from corrosion.