Late 80's bobcat 843. Anyone have some ideas to narrow down why my machine loses lift power? Here are some details. Starts up fine and can lift a load of gravel ok but maybe after 5 minutes running half throttle the lift arms do not want to go up and as time goes on, the only way to raise them is full throttle. Even then, they get slower. Then no lift at all. Checked the hydraulic fluid level, No cavitation. Drive foward and back seems unrelated to lift. Tilt functions when cold but seems to fall when lifting the arms. It's almost like auto bucket leveling with auto dropping. Thanks jim