I purchased a boat that has this motor and power trim (2 cylinder) system on it. most of the power trim parts are there but they were never connected or running on the boat. So I have disassebled/cleaned and rebuilt the trim pump and am going through the rest of the system. The sticker on the side of the pump housing says to use 10W30 or 10W40. That is the sticker that was put on there in 1980. Should I put 10W30 or W40 in the system or should I use a fluid designed for trim systems. I like the price and availability of 10W30, but if I should use special trim fluid, I would do that instead. Thoughts anyone?