Looking for a little help as I try to save a few bucks without making things worse. As many before me have experienced, the tilt trim motor on my Yamaha 9.9 leaked and was corroding. I took off the cover, cleaned it up and got it working better. Seems now I might have lost a little trim fluid in the process? Motor runs but struggles to raise the unit. Question: Is the refill hole the hex bolt or the flathead screw in the picture? Yes I realize the flathead screw on the side (not pictured) releases pressure in the system to move the engine down.