Refilling leg oil on 1989 90hp VRO

I have a old 90hp 89 modle vro

I have a old 90hp 89 modle vro and am in the process of changing the lower leg gear oil. I drained the leg oil by removing the largish screw from the bottom of the leg near the skeg. Now I'm not sure how much oil to put back into the leg. There is a phillips head screw near the water intake and another largeish flat headed screw like the one used to drain the oil near the cavitation plate. Both seem to lead into the lower leg gear oil chamber. Do I fill all the way up to the screw near the cavitation plate or only as far and the phillips head screw near the water intake? Why are there two screws anyway? Thank in advance.
Chris

"Chris, the screw near the wat

"Chris, the screw near the water intake is a set screw for a bearing - so leave that one alone.

The large one near the cavitation plate is the vent screw for the lower unit. You should refill the lower unit with it in a "normal" upright position.

Remove the upper vent screw and force your gear oil in through the drain hole until it just comes out the vent - then button everything up.

Do it quickly so you don't lose too much - but a bit of room is ok because the oil does expand "slightly".

It is filled in the upright position so that all the air is forced out the upper vent...."

"Thanks for your advice. I did

"Thanks for your advice. I did however unscrew both screws, the screw near cavitation plate and the screw near the water intake to see where they lead. I have just retightened the one near the water intake is there anything i should do or have done when i reinstalled that screw (the phillips head near the water intake)?
Thanks again Chris"

"You are probably fine if you

"You are probably fine if you didn't move too much around - that screw goes in to help stablize a bearing on the driveshaft (just before it connects up with the lower gears) and I would imagine it is to prevent torquing etc.

So as long as you tightened it back up and didn't pull on the driveshaft while you had that screw undone, you should be good to go..."

"I didnt move or mess around w

"I didnt move or mess around with anything while I had the screw out, so it should be good to go

Thanks again

Chris"

That screw only locates and po

That screw only locates and positions the pinion bearing.It has nothing to do with the driveshaft.Use a bit of sealer on that screw.Fill the gearcase from the bottom till oil comes out the top. Re-install the top screw and then the bottom.