Mercury 25W-40 oil for outboards

[ledslinger]

Mercury has two 25w-40 synblend oils, one for inboards and sterndrives, and one for outboards.

Anyone have any idea on how these oils could differ other than the label? Would a stern drive and an outboard really require a different formulation?

 

[hate2work]

I found this on google. It appears that outboards run at a higher RPM than inboards.

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QUICKSILVER 4-CYCLE ENGINE OIL - 946ml [32fl oz][1 qt] 108LUB802837Q

Quicksilver 4 cycle (or 4 stroke) marine engine oil keeps your engine cool when the going gets hot. Multi viscosity 25W-40 oil that you can run during the boating season. Used regularly, it will reduce engine wear and corrosion and protect against chemical attack, keep pistons clean, prevent rings from sticking and inhibit rust and sludge deposits

QUICKSILVER 4-STROKE OUTBOARD OIL - 1 LITRE [33.8fl oz] 108LUB802833Q

Formulated specially for 4 stroke outboards. Outboards typically operate at 5000-6000 RPM at wide open throttle, almost twice as fast as 4 stroke automobile engines. Normal automotive lubricants are not formulated to handle thse speeds. Quicksilver 4 stroke outboard oil contains special additives making it ideally suited for this application. They help reduce wear, scuffing and scoring, prevent the formulation of rust and sludge and inhibit the formulation of unwanted damaging foam

 

[Bluestream]

Sterndrives run at 4200-4800 at WOT, so not much differnce really. The BRP 4-sroke jet drive engines run at 8000 RPM at WOT

 

[azsynthetic]

1200 rpm is a big difference at WOT, especially with big motor 200-300hp 6 cylinders.

 

[ac_tc]

Maybe a tad moore foam retardant.
We have al seen HDOE for diesels turning 1800 rpms used sucsesfully in [censored] motorcycles turning 12000 rpms...
so that gives?

 

[azsynthetic]

Motorcycles that turn 12,000 rpms "continuously" do not use HDEO. They used high quality name brand "motorcycle" oil. Joe Blow and parking lot racers use HDEO in their motorcycles. You will not find HDEO in any professional racing winning circle.