Motor loweres by itself very slowly after being tilted up with power trim.

[coachkwj]

I have a 2001 70HP Yamaha that I have not had a single issue with. Until now. The motor seems to drop down slowly on it's own after trimming it up to fish shallow water etc. I checked the system and there are absolutely no signs of leakage. I filled the reservoir and ran it up and down several times and topped it off and it seems to have gotten better but still does not stay up. I did this while it was on the boatlift and not on the trailer with the tongue down but I don't think that would have let me put that much more fluid in it but I could be wrong. Before replacing all the seals etc any suggestions? Motor sounds a little different that it always has at times. Could it be the motor?

 

[gm280]

Sounds like you have some leakage but not leaking externally. It seems like it is leaking pass the internal seals or "O"rings. Kind of like a leaking master cylinder on a vehicle. So it may be time to do a rebuild with new seals, "O" rings and gaskets and even check valves if it has them. Just my uneducated guess though.

 

[robert graham]

My 1999 C90 Yamaha has very slowly leaked down for years...especially overnight. I don't much worry about it. If I want the motor to stay up then I set the tilt lock.

 

[99yam40]

if you were able to add fluid there is an external leak some where

 

[fazerpaul]

First try tightening the manual trim/tilt release valve on the starboard side of the bracket!

 

[dpmsgeek]

I had a similar issue where I would take the motor off the transom saver and the hydraulics would lower on their own. I pumped all of the oil out of the reservoir filled it back up. With he motor on the trailer lock, I disconnected my lines and ran the pump up and down to flush old fluid out of the lines. I wound up having a little water and some sludge come out. It only takes a small amount of water to mess things up. Before reconnecting the lines and topping off the reservoir, I manually lifted and lowered the motor the get the last bit out of the rams. After connecting everything backup I no longer had the issues with the motor working itself back down.

 

[coachkwj]

Its not the valve. Was tight and when loosened motor dropped down pretty quick. Tightened it back up. Still no signs of a leak. Im totally baffled. Dont want to start replacing seals etc if it might be something else. Might try completely draining and re-filling. This has me nuts. Not really a major issue but cruising along in shallow ater and then all of the sudden not moving is annoying.

 

[James R]

Follow what dpmsgeek suggested. Just a little contamination can prevent an internal valve sealing. Can also prevent the manual release valve from sealing.

 

[coachkwj]

Sounds like an easy enough fix if it works. have the fluid and the time. I will give it a shot.
Thanks to all.