Have put 20 hours on my new Donzi 27 ZR with a 496 HO.
As 25W-50 oil is not available locally, my only option was to put in Mobil 1 0W-40. Pressure at idle is 20 and at WOT 40 lbs.

Do you guys think this is fine ??

Furthermore, today while testing and keeping eyes fixed on the Oil pressure gauge I accellerated only to notice that my outdrive was half way up on the Drive gauge....hope no damage was done. I corrected this before hitting 3,500 rpm and then shifted at idle and heard nothing strange...hope I got away with it.

All input is highly appreciated.........

0W-40 is too light. You should run 15W50 Mobile 1. You should be running more than 40 psi of oil pressure at WOT.

Your u-joints are most likely fine after running the drive a bit high.

I run straight 40w.

thanks for the quick replies. highly appreciated.

alternatively i can locate Mobil Super 20W-50 locally.
would that be better ??

should i drain the Mobil 1 0W-40 straight away or can I put a few hours on it withot harmin the engine ?

I assume that you are still under factory warranty. You need to make sure the sysnthetic will not void your warranty!

I posted a thread about this before. My 2003 owners manual specifically says synthetic oil is not recomennded.

Straight away. Then, like pachanga said, read your owners manual and use the oil they recommend.

Get rid of the 0-40wt asap. Mobil 1 is made in 15-50wt. Use that, a quaility straight 40wt, or Merc oil.

I'm not saying the synthetic isn't superior. I got it straight from Merc. Racing brass that the only reason they told me not to use synthetic in my 525efi's was that "they haven't tested it yet". Personally, I think a good synthetic is better in a high reving big block in the marine industry. However, MR said their oil is formulated to reduce moisture obsorbition in a marine application.

In a 496 Merc engine run 15-40W 15-50W 0r 25-40W period! Absolutly no 0-anything oil!! As for brands , many good ones out there, Mercury, Royal Purple, Amsoil, certain Mobile 1's etc.

Regards,

Ray @ Raylar