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What oil treatment if any should...

marklgunn
Guest Contributor
What oil treatment if any should I use with 454 mercruisers on boat that stays in ocean water?
4 REPLIES 4

wingless
Rising Contributor
The motor oil I use in my Mercruiser 454 MAG MPI Horizon engines is the Mercury Marine 25W-50 synthetic blend 4-stroke marine engine oil. I do not use additives.

On my boat I designed and installed a custom 5-zone high-volume high-pressure oil change system that will suck out the oil sump in ten seconds. It comes out like a fire hose. This is part of my 5 minute oil and filter change system, enabling me to keep fresh engine oil for long life.

Mine is stored and operated in salt water.

IMO the big engine issue is the raw water (salt water) cooled exhaust. This causes exhaust manifold, riser and elbow corrosion damage, creating the possibility of raw water intrusion into the engine.

Before I redesigned my custom exhaust cooling I was getting about three years on genuine Mercruiser parts before I was unwilling to continue usage. I would perform an annual inspection of the solid wall thickness between raw water passages and exhaust gas passages.

Now my exhaust is rinsed w/ fresh water, soapy water then Salt Away. When done I drain my exhaust bone dry until the next usage. It looks like my expensive exhausts will now have a very long lifetime.

Harley1
Guest Contributor

how did this hold up?

 

Captain_Rick1
Guest Contributor
Marklgunn. No additives are necessary if you religiously change the engine oil and all filters at the end of each season or 120 hours whichever comes first. Not many owners have the ability to engineer oil change systems so if you do not have one installed REVERSO is the Sea Ray standard. The biggest maintenance enhancement you can do is install a fresh water flush for mains and gen set (if you have one). Engines should be flushed at idle for 15 minutes each using dock water if the boat is going to sit unused for x number of days. I say a week. You should research fresh water flush systems to get a better idea of what you need to do.

Stu2
Guest Contributor
The year your engines were built will determine the correct oil. Engines with flat tappers use a different oil than those equipped with roller tappets