l took the boat out yesterday and noticed my trim was moving slow.. It just probably just need fluid right? Well where do l add the fluid and what should l use?

Mercurys' pwr trim unit is mounted seperately from the motor, somewhere in the stern. it has a built in resevoir, on which the level is marked. Slow moving trim usually indicates something other than a fluid level problem. This could be a soon-to-fail pump unit, the wrong type of fluid, low voltage to the pump, & so on. There is some variance in the type of fluid used in different years. Fluid type should be marked on the pump resevoir, if not, take the engine serial# to a Merc dealer.

What fluid to fill the trimpump can depend on the year your boat/ engine combo is and what kinda fluid is in there now.
When located take a sample of the oil, thin- red or clear is atf or steering fluid anny other would be engine oil.
5w30(40) motor oil is common used, they dont mix !
Did it move faster before or do you think it moves slow?

Frank