Allright guys:

I was concerned about going from Mercury Racing's 25-40 to Mobil 1 15-50 in the 525 efi. I called Mercury and they said that it probably works great but that they haven't tested it and know that their oil works fine, so that's what they stay with. He did say that if the engine failed and they found it was the oil's fault, then the warrantee wouldn't be good.

What do you guys run and think?

I run Mobil 1 either 15-50 or 20-50 in my 575, I'm pretty sure my manual even says to run syn. As long as you meet the SAE ratings they specify (AP, AG etc. they can't claim anything.

OK- looked it up in the service manual..

"Preferred oils
Premium grade 20W-50 automotive oil SJ, CF/CF-2 rating"

Can't find anything about use of syn except not to mix oils.

Ron play it safe and run the Merc stuff....the last thing anybody wants is a warranty issue that they wont cover because of something like oil. Once the warranty expires then go with the syn. just my .02

Angel

Most of the guys, I know that are racing, are using the M-1 15/50.

Thanks Guys:

Maybe I should stay with the Merc recommended and then switch after the year warranty to be safe. Again, thanks for the input.

Ron

I know Jo uses the M1 15-50 in the F2 boat.
at least thats what he told me...
so now thats what i use.

Something else not mentioned, I think it's universally agreed that break in should be on dino oil.