I am having toubles with the trim unit on my outboard. It is not going up or down, but you can hear the pump running. It also sound as it there is air going past the impeller. The motor is a '78 75hp evinrude.
have you checked the fluid in the reservoir ?have you checked the manual release valve to be sure it is closed? if these are ok and the motor is running then you probably have a valve problem in the pump.
