my trim and tilt issue has gotten worse.... when I'm idling and I trim the engine down the engine jerks the entire boat.... today I had to tilt the engine up 100% to get onto the bank and when I got back the engine was stuck. The trim motor was running and both up and down button were working and sounding the trim motor but the engine wasn't moving...
Keep in mind here..... In the up mode the lifting is in full hydraulic mode..... In the down mode, the unit is simply releasing the hydraulic pressure of the center tilt ram and allowing the engine to drop via gravity. This gravity mode exists until the engine hits the trim rams at which point hydraulic pressure takes over to pull in and keep the engine in place hydraulically.
What has happened is that the nylon bushing on the center tilt ram has become corroded with salt between the outside surface of the nylon bushing and the ID top surface of the ram rod. This effectively causes the nylon bushing to grip the retaining pin so tightly that it squeals and will eventually seize up solidly.
When this happens, the up mode will be slow due to friction. When the engine is at full tilt or simply tilted up past the trim mode to some point... when you attempt to trim down, the engine cannot drop via gravity due to the bushing tightness, so the trim rams pull in first after which the center tilt rod takes effect and starts to pull the engine down hydraulically.
Watch the actual operation of the trim and tilt rams and you understand the drift of what I'm explaining.
The cure is to remove the top tilt cylinder retaining pin and the nylon bushing(s) of the top section of the tilt rod, clean all of the corrosion away, grease and install new bushing(s) if needed.
Yeah... it's one hellava job, I know... been there, done that, many times. This is gospel, no guess work! Wish you luck.