Suprisingly there isnt alot in the search about this...<br /><br />I have an 1959 18hp Evinrude, model 15028 and it requires hypoid l/u oil. Unknowingly I bought some Pennzoil high viscosity 80-90 GL5 stuff. According to the Pennzoil website they say it is ok...what do you guys recommend for the application at hand?