1977 OMC tilt issues

Hello, folks,
Thanks for allowing me to become a part of this group. I hope that Ican contribute as much as I will ask you for advice on my boat.
I picked up a 1977 OMC tri hull in a water heater install. The boat sat for year's so I needed to do quite a bit of work to make her run correctly. Now that I have the run part taken care of I am now working on the engine tilt. The motor lifts the front of the motor fine. But as soon as I turn the key off the motor begins to drop down. I cannot see any visual leaks so I am at a loss as to what might be happening. Any suggestions will be considered.
Thanks,
Daniel
P.s. It has the 235hp motor

likely leaking internally past the piston seals inside the rams - can buy seals from evinrude, or match them up to Parker seals at a local hydraulics place. They use the Parker "T" seals inside. Select the stern drive 235 and look for "with selectrim" for the part numbers


http://parts.evinrude.com/Index.aspx?s1=17e2csuj5jl62t07bl61608vq7&catalog_id=5&siteid=2

hystat said:

likely leaking internally past the piston seals inside the rams - can buy seals from evinrude, or match them up to Parker seals at a local hydraulics place. They use the Parker "T" seals inside. Select the stern drive 235 and look for "with selectrim" for the part numbers


http://parts.evinrude.com/Index.aspx?s1=17e2csuj5jl62t07bl61608vq7&catalog_id=5&siteid=2

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Thank you for the advice. I went ahead and installed a new tilt mechanism and bled all the old fluid out. I also dismantled the heart of the motor and cleaned it up and put it back together properly. Once I was comfortable that there was no air in the line I buttoned everything up. New tilt works great.. however, I am still watching my motor ease back down., i was hoping for the easy way out.

Plumbed1 said:

i was hoping for the easy way out.

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I bet you'll find those mounts/rams are pretty simple to work on - just don't use a vise or pliers on the shiny part of the rod