Tilt/Trim Slipping

[sherboat]

My tilt and trim work, but won't hold in the up position. It only takes a few minutes for the motor to return to the down position. I suspect maybe the hydraulic fluid level is low. Anyone have experience with topping that up? Is it easy enough to do, I am fairly mechanically inclined, just haven't tackled this task before.

'88 Yamaha 90

Thanks in advance.

 

[Island Fish Lifter]

check that the manual release is closed. If you dont know what that is, im sure a 100$/hr shop'll tell you!

 

[bee15]

rams might have a leak or a worn out o-ring in pump allowing pressure to escape

 

[Paul Burak]

check this link you'll find the answer http://www.marineengine.com/cgi-bin/discus/discus.cgi

 

[sherboat]

A quick update in case anyone is interested. I picked up a repair manual so that I would know my way around.

I purged air from the system through the manual release valve. Minor improvement, but still slipping. Checked the hydraulic fluid level, and it is at the correct level. Started to disassemble the cylinders to look for bad o-rings, everything looks good. I am suspecting the o-ring on the manual release valve. Unfortunately it appears it can't be removed without removing the whole tilt unit from the clamp bracket. I have disconnected everything, but it doesn't look like the unit will physically fit out of the rear of the clamp. Looks like I might have to pull the motor to get at it. I read somewhere that it might be possible to move the starboard side of the bracket out a bit, but have to be careful with the steering. Anyone know if that is possible?

I'll try and post some pictures in the next few days if I have time.

Cheers.

 

[reelendealen]

I wish I could have read your post before you tore down the cylinder. Sometimes the pressure release screw has a c-clip on it that you can remove and the p.r screw will come out. But if that doesn't work you can take off the starboard side of the unit, you do not have to remove the motor. Undo all your steering, take out the two bolts you have mounted to your transom to hold your motor on, there might be a couple more holding it into the trim ram and walaa! It's off, make sure you have your motor supported appopriatley as there is not much left holding it up. Those pressure relief screws generally have 3 little o-rings on them and there tapered, each ring restricts a different chamber. Even if they look perfect replace all 3. Nine out of ten times, that is the reason it is dropping.

 

[sherboat]

Thanks reelendealen. The pressure release screw does not appear that it would fit our through the access hole through which you can adjust it. Hence the need to remove the unit. I will try pulling the starboard side bracket to get at it. Thanks for the help.