Tilt trimwon't go down.

[NMB]

Hi,
I have an older,1981,Yamaha 85AET on which the tilt ram needed attention.
I removed the complete unit from the outboard,replaced the seals inside the ram and have purged the air.The unit is sitting in a vice.When I trim down the tilt ram will go down but the trim rams will not.
When I open the manual release valve I can push them back with my hand and trim them back up via the motor.
I have also replaced the seals on the manual release valve and the main valves.
So what have I missed? It worked before but dropped the motor so I assumed the O rings were worn. I didn't touch the trim rams as they held the engine when it came down that far.
It is the 688 which was installed on the '84 90HP in the US of A. 1984 90ETLN Yamaha Outboard POWER TRIM TILT ASSY Diagram and Parts
All advice appreciated,Thank you.

[boats.net]

They need the weight of motor to push them back down, should be ok once you have it back on outboard.

[ohsoslow]

I had a similar problem with my unit, pulled it out, then put it back in and refilled with fluid etc. Trimmed up mint, tilted up and down mint, but wouldn't trim down. (would go down fine with manual override) But, after bleeding it over and over and over and over again, letting it sit, then bleeding it over and over again (you get the point) It finally started going down slowly, and then faster and faster until it's back to normal. Perhaps yours just needs to go back on the motor, and spend a bit of time bleeding it all out.


When looking for solutions to my problem, I came across a guy saying that the relief valve might be stuck, and to jump up and down on motor, while someones standing on the front of the trailer, and someone else is pressing the trim down button! So if all else fails you could try that?! :P

[NMB]

Thank you for the replies,well I have totally dismantled the unit and waiting to draw down for the mortgage to change all the seal and O rings, figured they haven't been done since it was assembled.£20/$33 for one of the seals to $18.60 here but it's the p&p that takes the good out of it.
Still I have all winter to sort it.Thanks again for the advice.