Adding fluid to tilt/trim on a '77 Mercury 850

[PPP]

My tilt/trim motor & fluid tank is located inside boat near the transom. Is there a fast, easy way to add fluid? I only find a very small threaded opening on front left side of the fluid container. Seems there ought to be a vent for air escaping as the fluid is being added. Also, should I be using 5W30 oil (as some forums say) or hydraulic fluid?

 

[merc850]

Re: Adding fluid to tilt/trim on a '77 Mercury 850

In this photo you can see the large fill hole and the vent and the manual says 5W-20 oil.

 

[Chris1956]

Re: Adding fluid to tilt/trim on a '77 Mercury 850

The fill hole is a round head, slotted screw on the right hand side of the resevoir. Stick a Q-tip in there and see what is already in there. If it is brown and clear refill with motor oil. (My manual said 5W-30). if it is clear red, refill with Dextron II ATF. You need to use a small funnel.