just wondering is a SAE 90 GL-5 oil is ok in the Yamaha stern drive ?
In the manual it says SAE 90 GL-4 but in the new brochure for yamaha (link below)
they spec. GL-5 for the stern dirves?
does anyone have any expiririence using a GL-5 ?
oh and would it matter if you mixed a small amount of GL 4 (left in the pump) ?