Re: 70 hp johnson tilt and trim nightmare
That's caused by the steering tube nuts being too tight and they're binding somewhat. This creates friction which holds the engine in a tilt position due to the tightness. The engine normally lowers first due to gravity, then after dropping to the trim rams... hydraulic pressure takes effect.
The solution is to loosen one of the steering tube nuts a turn or so, then hold a 2x4 piece of lumber against the side of the swivel bracket, hitting that piece of wood with a good size hammer to jar the swivel bracket sideways slightly sideways. Grease the fittings after the problem is solved and snug up that loose nut as needed.