1991 Evinrude 225 Ocean pro trim problem

[carmariner]

Yesterday when loading my boat on the trailer the power trim did not raise smoothly, it bounced up. Once on the trailer I lowered it and again it bounced while going down, not smoothly. I started to remove the plug to check the fluid and when I loostened it fluid sprayed out so I did not remove it. Should I block the engine up when I remove the plug and does anyone know what the problem might be. The unit raises and lowers it just bounces up and down. Any help would be appreciated. Roger...

[boats.net]

Raise up all the way to check fluid level and fill until runs out.