Boat Motor Injector Oil - Switching to Synthetic

[Hotspotter]

Should I be purging the system of the old dino-oil before adding the new stuff? Can I dump the new stuff in with the old? I'm really low on the old stuff anyway.

Thoughts?

Joel

[Pat K]

Run the dino oil as low as you can and then add the synthetic. I've done it that way with a 75 and a 90 hp Mariner with no problems. Any oil that meets TCW3 standards will mix with any other TCW3 oil.

[theoilman]

Absolutely, just add the synthetic with the tank low. Most are extremely difficult to purge, or at best very sloppy to attempt, don't even try. Normal recommendation to change is to run until the warning light/buzzer goes off, then just fill with the synthetic.

[ChuckN]

The synthetic oil is compatible to mix with the other oil, so you can do whatever you like. No worries.

[Hotspotter]

Thanks for the great advice gentlemen!

Joel