i just picked up a lake and bay 17' with a 99' optimax 135, right now it is oil injected but i want to direct mix the oil to prevent an issue if the injector fails since it is an older motor. i was reading the ratios for oil to fuel online and it sounds like it is 50:1. Does this sound right? any sugguestions or tips and how do i go about shutting off the injector. thanks