[pair of jacks]

I have only used Quicksilver (Mercury) oil, the Premium Plus version especially for Optimax. I was always told not to mess with anything else and I didn't. I've talked to quite a few Optimax owners and service people and the powerhead is a problem on the older Opti's- they are replacing it with a new version that is supposedly much better and free of bugs- just as long as they do it under warranty !!