Mercruiser power trim issue

[sandyhk]

I have a 1974 mercruiser and it wont trim down. When I switch the lines on the cylinders it will work up and down , and the switches are reversed. Then I put the lines back correctly and it trims up fine and when you press the down switchthe pump runs but the outdrive doesnt move. Confused and need help.:confused

 

[Howard Sterndrive]

Re: Mercruiser power trim issue

don't suppose you overfilled the reservoir?

 

[Don S]

Re: Mercruiser power trim issue

Sounds a lot like you may have a salt water boat and have corrosion in the trim cylinders around the rods. The pressure in the pump is higer on up than down, when you change the lines around you use the high pressure for down. Up would still have more power, even from the down circuit. I can't explain it exactly, but if you go up to the Adults only sticky at the top of this forum and locate the service manual link, you cn download manual #4 and have a read at the trim section on how the system works.

 

[Bondo]

Re: Mercruiser power trim issue

When I switch the lines on the cylinders it will work up and down , and the switches are reversed.

Ayuh,... Switch the Switches.....

 

[sandyhk]

Re: Mercruiser power trim issue

You were exactly right there were corroision around the rods ,took it apart freed them up changed 2 o-rings and it works like new. Thank you very much.