I own a 96 200 HP Yamaha Saltwater Series, and I am having a problem w/ TILT mechanism . It sounds as it is hydraulic in nature since motor works and trim works, however when trying to raise beyond trim cylinders height, hear swishing air sound and engine will not raise. Tried adding fluid but not really sure of the procedure, there is a allen key screw in bottom left, however fluid does not flow in. Suspect there must be a vent opening someplace else to allow it to fill. If someone can help with procedure, would appreciate.