I just purchased a new to me champion with a 225 opti merc on it. I was going to fill my oil reservoir and noticed the oil I got at academy was synthetic blend. Quicksilver of course but wasn't sure if I could use it with current oil. Someone please help me out here.

Thanks in advance Rut

On older engines, I try to always stick with whatever oil it's been getting. If you don't know the answer to that, then I would say to just pick whatever you like and stick with that.

Premium Plus is rated for Optimax. I believe one of the specifications for TCW-3 is to be able to mix any brand and not have any ill affects. Problem is I'm not sure Mercury Optimax/DFI oil is TCW-3? But they do claim it will mix with other oils. I know Quicksilver Premium and Premier+ are TCW-3.

Personally I would run the tank down as low as you are comfortable doing and then fill it up with your new brand just to be sure.

That's good info.... Thanks guys

I have been running a trouble free 225 Optimax for 13 years. I've never used any oil except the Mercury DI.

The BBC has excellent forum on this.See Below:

Please consult your owner's manual, or http://www.mercurymarine.com for the BEST recommendations on each of these items!

This list will be updated as additional information is requested- check it regularly for the most current information!

Oil:
-These are the "top recommendations". Refer to your owner's manual for other oil specifications!
-ALL EFI/CARB 2.4/2.5/3.0L (2-stroke) Engines: Mercury or Quicksilver Premium PLUS
-All STANDARD Optimax (75-250): Mercury or Quicksilver DFI/Optimax Oil
-ALL ProXS Models: Optimax/DFI Oil. Mercury or Quicksilver Premium PLUS is acceptable, but Optimax/DFI oil is RECOMMENDED due to a better additive package to help combat carbon deposits.
-ALL Racing/XS Models: Mercury Racing 2 Cycle Oil pn. 92-8M0078011, Mercury Racing Gear Lube pn. 92-8M0078015. Premium Plus oil may be used as alternative ENGINE oil.

- (Note..... there was some conflicting information on Merc's Website- follow this recommendation for the latest information as it's released!)

NOTE: Mercury/Quicksilver Optimax/DFI oil, and Mercury/Quicksilver Premium PLUS are totally compatible with each other. Although you should use the CORRECT oil, you can switch to the recommended Optimax/DFI oil, simply by adding the correct oil to the tank.