Re: Lower Unit oil for merc 25 hp 2 cycle
If it is Merc or Quicksilver brand and is marketed for OB lower units then go for it. The 90 wt is what you use down there but the kicker is the additives, the one in particular is the sticky one that makes the oil adhere to the steel surfaces in the LU helping to prevent rust WHEN water finds it's way in. Normal GL-1 or 5 don't have that additive. On high HP, high performance engines they market a lube marked especially for that kind of service. I get my lube at WW in the sporting goods dept.
HTH,
Mark
