One question I’m frequently asked is: Can I mix oils? I’m a bit of a purest. I try to refrain from mixing oils, but I know that others mix oil with reported success. In an effort to give you the best information, I took a look at what the experts at Mercury Marine have to say.
To my surprise, they wrote that Mercury OptiMax oil can be mixed with other premium oils (from Mercury, of course). They wrote that more the oils can be mixed together without a negative impact on the outboard. There you have it; the experts have spoken!