Sure.
So is Mobil 15w-50
So is Valvoline VR 20w-50 conventional or synthetic
So is plenty of other oils. But above , including the Mercruiser oil, are the top 3 fav’s.

Hello

I just had 11 hours on my Mercury 500 EFI engine after complete rebuild.

The oil change ?

Quicksilver 25w40 synthetic blend or the last Quiksilver 25w50 synthetic blend ?

The best choice ???

thanks

most people on the boards are using Mobil 1 15-50, or something similar

This. Wally world has good price.

Hello

But in Europe,

not Mobil 15w50, not Valvoline .....

then run what ever you like, personally I dont like synthetics in a marine application

Great post, some great info!

Found this link, never seen this one before, shows all the Mobil one oils, and how they are actually different.

The 15W-50 is 1300 PPM of Zinc

https://www.mobil.com/lubricants/-/m...pecs-guide.pdf


What's interesting as well, they make a V-Twin oil 20W-50 which is 1750 PPM Zinc.

Oil debates are endless. Everyone uses different oils and 99% have no issues so they think their oil is "the" magic oil. The truth is nearly any oil will work in nearly any engine. Even the super duper engines..... 99 cent wal mart oil will work as well at $12 VTwin in 99% of marine motors. You will never know the difference after years of use.

that^^^^^^ well maybe not the 0W20 lol

Friction modifiers and viscosity improvers are the additives found in modern "car" oil that you DONT want in a performance marine oil.

Car oils use a lightweight BASE oil (the 15 weight in a 15w40) and then put in "longchain viscosity improvers" to yield the 40 number. A marine application will "chop up" and "use up" the viscosity modifiers pretty quickly, leaving the base oil only (the 15w).

The friction improvers/modifiers are added to make up for the removal of zinc and phosphorus (both of which are counterproductive in zero-emissions goals). These also are a poor crutch vs the proven (but less green) zinc and phosphorus.

So what Merc does is to mix 25w and 40w base oils..

And outside of Merc oil, you have to understand the "secret language" of modern motor oils

All 5wXX and 0wXX oils are loaded with boat-unfriendly chemistry.

All 20wXX oils are considered NON MAINSTREAM AUTO/TRUCK products and can get away with giving more of what you want and less of what you don't need. Keep that in mind.

Any oil labeled MOTORCYCLE OIL will be free of friction modifiers because otherwise the wet clutches would slip like heck.

Any oil labeled LAWNCARE or UTILITY oil will have more zinc and phosphorus in em. Mower engines are a similar duty cycle as a marine engine. Mower engines typically run flat tappet cams, which require zinc.

Racing oils are a mixed bag. Some are labeled racing oil in order to allow them to use a formulation that is desirable for motors and undesirable for catalytic converters - while still containing decent detergent package and good corrosion control. Other racing oils are true racing oils that are low detergent and zero extended anti corrosion additives and are designed to be run hard and immediately changed - that's not what you want In a boat.

Sooooooo. There's more to it than you'd think on the surface.

20w40 motorcycle/marine/lawnmower oil is your friend.

Nothing wrong with a synthetic as long as it meets the discussion above..

Full synthetic motorcycle oil is great.
V Twin labeled Mobil 1 is fantastic stuff.

But honestly, lawnmower oil is best value.