Please don't tell my 1996 Mariner 175 efi that WalMart oil is junk. That WM and Penzoil (when I couldn't get WalMart oil) are all it's ever had run through it. Just had an injector service done, compresion and leak down test. Old engine is still at factory specs after unknown hours. I could go in to a long diatribe about oil blending facilities I've been into and what I was told and shown numerous different brands of 2 cycle oils coming out of one huge blended batch tank.There are differences in the additive pkgs for DFI vs regular two cycle oils but for each category, they are pretty much the same stuff in different bottles.Oil color is simply a dye added, nothing else.

Generally the same concept for transmission fluid, motor oils, gear oils, and just about any other lubricant you can get your hands on. There’s a spec for a reason.

Thank you everyone!

I spent some time researching race oils several years ago when I was drag racing a lot, running stock eliminator class.

As some have said, only a few suppliers of the base stock, and all meet spec. There is some difference in the additive package different companies use. Some better than others.

I will use a good DFI oil. That makes sense and not much cost difference in amount used.

Thanks
Ken

Go look at the MSRP of any of the oils and it will tell you who makes it. Pennzoil is the only company that has their own refinery everybody else uses a 3rd party contractor to refine their oil. So neither Mercury, Yamaha or Evinrude makes their own oil.

So between Pennzoil, Quicksilver, Valvoline, SuperTech etc, Which 2 stroke oil is best in y'alls opinion? I've run Pennzoil in my 92 175hp Mariner & 06 90hp Yamaha for years.

If it just needs a regular 2 stroke oil and not a dfi oil it doesn’t matter one bit as long as it’s tcw-3 certified

I'd stick with the Mercury DFI oil.