Merc outdrive only trims down halfway

[Bondo]

Re: Merc outdrive only trims down halfway

Ayuh,... Each cylinder should be able to stroke it's full travel with minimal resistense, without the oil lines attached...
Does 1 work harder than the other when manually moved,..??

 

[Jstep]

Re: Merc outdrive only trims down halfway

Ayuh,... Each cylinder should be able to stroke it's full travel with minimal resistense, without the oil lines attached...
Does 1 work harder than the other when manually moved,..??

They're both extremely difficult to move manually. When I rebuilt them, it was a bear to get the piston rods out of the old inner cylinders, and even more difficult to get the piston rods with the new seals into the new inner cylinders. So much so, that I had to pound them in with a rubber mallet.

Being that I've never dealt with hydraulics before and they were nearly as difficult to get out of the old inner cylinders, I figured this was normal. Guess not. I'm not sure what the cause of the excessive resistance was. The only seal on the piston was the quad ring (#18 in Fig. 4, pg 7A-29 of manual).

Could the piston itself be screwed up and causing this to happen?

 

[fishrdan]

Re: Merc outdrive only trims down halfway

Do you have a hydraulic trim sender on that 69? The trim sender has a bleed screw on each side (top) and I guess you could get the system's balance off if it's not bled right.

I haven't bled mine yet, but am invisioning a problem like yours if the hydraulic trim sender is not bled correctly.

 

[system-f]

Re: Merc outdrive only trims down halfway

My 71 has a similar problem, but it ALMOST goes all the way down. This problem happened after replacing a line so I am pretty sure my problem is a bleeding issue. Though, the manual does say that if it won't return all the way then it probably has air in the system. I manually bled them and that helped some. When I pulled my cylinders off they were pretty tought to force back in by hand and I am 99% sure nothing is wrong with them. Once the cylinders are free of all oil they are easier to move.

 

[Jstep]

Re: Merc outdrive only trims down halfway

I don't have the hydraulic trim indicator sender pictured in that page from the manual. I see the bracket where it should mount, pictured here, but I don't have the sender.

I do have two lines going into the reverse lockout valve on the left side of that bracket.