If you honestly can find something better than the AMSOIL Dominator 15w-50, I would be extremely surprised! I would recommend that, along with their oil filter, the EAO-24.

+1 although the Amsoil 20w50 is also good. I have spoken to the Royal Purple tech support people (and the Amsoil tech support) many times, so I would not veto Royal Purple either. What you want is something in the 20w-50 range or 15w50 range unless you boat in colder northern temps.

I use mine about 50-70hrs a season.

So it looks like Amsoil, or Royal Purple 50 weight is the ticket. What is the very best filter?

What drive lube do you recommend?

I've got 400 hours on my 496. Mobil 1 15W50 and Wix 51086 filter. Has never touched a drop of oil and always maintains good oil pressure. Still runs like new. Amsoil Marine Gear lube in the drive.

I would not run straight 50 weight.

This looks like a nice deal for the Amsoil oil

https://www.theoilhub.com/AMSOIL_Dom...G_4?src=Google

Mobil 1 V Twin with a wix racing filter.

PS. I would run any oil 70 hours, but that's just me.

50-70 hours a season is 2-3 oil changes; about 25 hours per oil change, NO more than 30.

I run 7 quarts of Mobil1 15w50 and 1 quart of Lucas Oil Treatment (Synthetic, black label) with Wix Racing filters from Napa.

wow lots of different info here. My buddy gas 6.2's would you still run one of these oils in that?

Changing oil every 25 hours is ludicrous.

If anything oils, and solvents have gotten better over the years. not worse, let alone engine tolerances, and build quality. Every merc 454 and 502 i have ever had, or seen got an oil change once a year, and they ran intot he 100o hours. no reason to think differently on these.

Now that being said if you run your boat at 5000RPMS all the time maybe so. But I personally use mine like a cruiser 99% of the time, its a 3500 rpms cursing at 42-44mph. and maybe a quick WOT run for a min or so (cleaning it out, letting them stretch there legs,and for fun). then back to normal.

This kind of operation does not even get the oil dirty in. I change mine every season. to keep fresh oil, and the detergants fresh on the sitting winterized motors.

I live in pittsburgh, and my mechanic says 10w-40 marine royal purple would be ideal. He said the 15-50 might be bad for cold starts