Ive had two different marinas tell me that most blown engines they see are from using cheap oil, is Tcw3 different from different manufactures. There sure is big price differences.

I really dont know but I certainly know castrol is alot better than pennzoil. I have learned from experience.

There is a good article on this in Bassmater, or Outdoor Life, I forget, magizine in the last couple of months.  The basic information in the article was; that the industry standard for TCW3 has just been changed, ie up graded.  The author suggested that you always buy the premium oil.  The only exception was the Merc Optimax which has it's own special oil.

Nick-Barr, What problem did you have with pennzoil?

I have run Itaska and Pennzoil synthetic in another boat that I own for 10 years. Have never changed the plugs, and they still look brandnew. A Mercury 150 efi with a ton of hours on it. It has only known 3 speeds, Reverse off the trailer, idle to the dock, and wide *** open from point A-B.

Do Not Use synthetic in a new motor. Needs to be well broken in before you do.

However Mercury says to run the premium plus in my 250 xs..Always do what they say while its under warranty!

Always run 93 octane in a 150 or larger. The mechanics always say 87 or 89.. Thats because it brings them more biz!!

I use Yamahalube. I was told by the dealer that the Yamaha outboard runs best on its own special brand.When I ran an Evinrude,I used Penzoil Premium.It worked fine for me.