'85 90 HP Yamaha Trim and Tilt

borncountryboy

Recruit
Joined
Jul 23, 2001
Messages
1
I am having a problem with the trim and tilt unit on my 1985 yamaha 90HP outboard. It seems to raise OK, but neither the tilt or the trim want to go down. I have to release it with the manual valve. I took it apart and replaced most all of the seals. The only thing that I didn't replace was the down relif valve. I have inspected the down relief valve and it doesn't look to bad, but even if it was worn I would think that the fluid would leak past it all the time and not hold its position, but mine holds its position fine. It acts like the hydraulic fluid has no place to go when trying to drive the cyclinders down. Does anyone have any idea what the problem might be or have a hydraulic schematic to help me troubleshoot this?????????<br />thanx
 
Joined
Aug 1, 2007
Messages
6
Re: '85 90 HP Yamaha Trim and Tilt

Did you ever figure this out? I am having similar problems on an '88 90hp yamaha. Mine gets stuck in the tilted upright position and won't go down. It is very slow raising and somtimes won't raise from the bottom position. I have got it to move by standing on the leg and jumping.... I know this must be bad.. but I was desperate. Any words of wisdom? Thanks.
 

Marc III

Petty Officer 2nd Class
Joined
Mar 26, 2007
Messages
104
Re: '85 90 HP Yamaha Trim and Tilt

My 1988 90hp unit is screwed up too! It wouldn't go down, so I opened the release screw and let it drop, after I re-seated it the motor would go further down but not up. How did you get your unit out? I braced the motor and unbolted each mount, one at a time, and couldn't get either to slide. I do hope somebody will help us.
 

grid

Petty Officer 1st Class
Joined
Oct 29, 2002
Messages
232
Re: '85 90 HP Yamaha Trim and Tilt

This is probably NOT the best way to handle the situation, but release the manual release screw, raise the engine until you can get to the fill screw on the reservoir and remove it. Put absorbent under the unit. Lower the engine manually; tighten the release screw. If no oil comes out of the reservoir, add it with a squirt can. Then try raising the engine electrically. Go up a little way, then down. Try this a few times until you get full movement. It's worked for me as many times as not, and truthfully, I don't know what I'm correcting when it does work.
 
Joined
Aug 1, 2007
Messages
6
Re: '85 90 HP Yamaha Trim and Tilt

I can't seem to find the manual release screw. I undid the fluid reservoir bolt and nothing came out. I'll top that up. Where is this release screw located? THanks a lot! I think that my seals need fixing because I can see a bit of fluid leaking out.
TOny
 

jl_photo

Petty Officer 2nd Class
Joined
Jul 30, 2007
Messages
108
Re: '85 90 HP Yamaha Trim and Tilt

are you sure that you don't have an electrical problem? the motor may be turning "up" even when you push the down button.

if the motor will not turn in the down position check the relay

there should be a relay box under the cowling
 

Marc III

Petty Officer 2nd Class
Joined
Mar 26, 2007
Messages
104
Re: '85 90 HP Yamaha Trim and Tilt

I feel confident my problem is not electrical. It was stuck in the fully tilted position, I kept working with it and got it to cycle up and down 3-5 more times before it stuck again. I believe I have a faulty valve or a failed internal seal. The fluid level is just barely running out the fill screw in both the up and down positions. I would expect the level to vary some.

fisholdschool - The release screw is accessed through the right mount. Clockwise to release and counter-clockwise to seat.

borncountryboy - How did you get your unit out from between the mounts?


P.S. I hate to hi-jack a thread, but maybe we can help each other until "someone in the know" notices us.
 
Joined
Aug 1, 2007
Messages
6
Re: '85 90 HP Yamaha Trim and Tilt

Thanks for the ideas. I don't think that mine is electrical either. I can always hear the motor trying to lift the engine up and down. It does change in tone as it is lifting... when it works... I really need to get a shop manual. THis is driving me crazy. I'll have to check it out in daylight tomorrow. Do you guys know whether or not you can remove the tilt/trim without taking the engine off?
 
Joined
Aug 1, 2007
Messages
6
Re: '85 90 HP Yamaha Trim and Tilt

I found the release screw :) Thanks. What do I fill up the reservoir with for a 88 - 90hp yamaha? THanks again for all the help.
Tony
 

Marc III

Petty Officer 2nd Class
Joined
Mar 26, 2007
Messages
104
Re: '85 90 HP Yamaha Trim and Tilt

Dexron III ATF is just fine.
 
Top