Power Trim Pressure Loss!

[starkyb]

I have a 75 hp Mariner. When trimmed up it slowly comes back down. I noticed grease built up at the top of the cylinder where the shaft goes in. Is there a bad seal somewhere and if so how do I repair it?

 

[Moody Blue]

Re: Power Trim Pressure Loss!

You don't mention the year of the motor. It is possible that the manual relief valve is not tightened and is allowing the fluid to bleed past the relief valve.

Other thing could be a broken or damaged relief valve. Same thing happened to my 93 40hp Mariner. I overtightened the relief valve and broke the plastic tip off. The replacement was about $16 and was easy to replace.

To check the seal at the top of the cylinder spray some soapy water on it after it is trimmed up. Watch for bubbles forming if there is a bad seal.

 

[TheToad]

Re: Power Trim Pressure Loss!

I am also having this problem when i bought the boat i was told the trim didnt work at all a couple of minutes and a couple relays later we have movement. But it will not stay up, it goes back down slower sometimes but for the most part it moves rather quickly.

the motor is a 88 mer 125 force.

 

[starkyb]

Re: Power Trim Pressure Loss!

It is an 88 Mariner. There is an oily substance where the piston goes into the cylinder. If it is a bad seal how expensive and involved is it to fix. If I keep oil in it would that keep the pressure up as long as it is relatively full and where can I get the oil from?