I'm having a problem with the tilt/trim on this motor. The tilt cylinder will tilt it all the way down, but will not raise it up. The only way I can get the motor tilted up is by turning the screw valve to manual and lifting the engine up. It sure seems like it's a trapped air problem. I followed the procedure in the service manual of lifting the engine 5 or 6 times checking the oil level at the end of each of these sets of 6. I have done two sets of 6 times lifting and I did add some ATF oil at one point. Each time I let the engine down slowly I can hear what sounds like air bubbling inside for a few seconds. It seems like the amount of bubbling that I can hear is significantly less than when I began but the cylinder still wont raise the engine. I read somewhere on here where it is difficult and time consuming to bleed the air out of the system. Do I just need to do more of these up/down cycles. If the problem isn't air in the system how do I determine the cause?