I have an issue with the unit on a 250 Yamaha 2000 trim/tilt not going down all the way. Seals replaced and it goes up and down fine until it gets to the two lower rams then it won't trim any further. I've researched and tried bleeding the air out of the system many time by raising it all the way then slowing lowering it by the manual release screw. It trims all the way down with the manual release but won't with the switch(new relay switch). I've read everything I can about removing the air but it seems like it has an air lock when it reaches those two rams. Any ideas would be greatly appreciated!