Out drive stuck up

[Marinemp]

Just bought my first boat I think I got hosed lol .. it's a 83 Starcraft islander with 140 merc... the out drive will only go down if I stand on it and have my wife hit the trim button to lower it or if I remove the line on the drive and bleed the fluid out.. what's weird is I can raise the drive with no problem but when I go to lower it the pump sounds like it "binds" up and struggles very hard and the drive doesn't move !? ... It feels like it's locked up somehow....

 

[achris]

Hello Marineamp and :welcome: to iboats.

No, you didn't get 'hoses'... (terrible word, don't know who thought THAT one up :facepalm. But you are right about it binding. The trim ram end caps have corroded, and the internal diameter has been reduced by the products of that corrosion. Consequently, the rod is being 'grabbed' by the end cap. As UP pressure is nearer 3,000psi, and it's being applied to the full surface area of the piston, the ram is able to extend. However, the DOWN pressure is much less, about half, and is applied to the surface area of the piston LESS the area taken by the rod where it joins the piston. The nett result is that there is less than half the force retracting the ram than extending it.

The fix is not to difficult, or expensive. Simply replace the end caps (and their associated seals)... Many people just clean up the caps, but it doesn't last long, the anodized surface has been compromised, so it will continue to corrode.... Easier and more of a long-term fix to just replace them and be done with it.

Chris.....

 

[Marinemp]

Hello Marineamp and :welcome: to iboats.

No, you didn't get 'hoses'... (terrible word, don't know who thought THAT one up :facepalm. But you are right about it binding. The trim ram end caps have corroded, and the internal diameter has been reduced by the products of that corrosion. Consequently, the rod is being 'grabbed' by the end cap. As UP pressure is nearer 3,000psi, and it's being applied to the full surface area of the piston, the ram is able to extend. However, the DOWN pressure is much less, about half, and is applied to the surface area of the piston LESS the area taken by the rod where it joins the piston. The nett result is that there is less than half the force retracting the ram than extending it.

The fix is not to difficult, or expensive. Simply replace the end caps (and their associated seals)... Many people just clean up the caps, but it doesn't last long, the anodized surface has been compromised, so it will continue to corrode.... Easier and more of a long-term fix to just replace them and be done with it.

Chris.....

Awesome thanks for the welcome and solid info ! I'll let you know how this works out

 

[Marinemp]

Hello Marineamp and :welcome: to iboats.

No, you didn't get 'hoses'... (terrible word, don't know who thought THAT one up :facepalm. But you are right about it binding. The trim ram end caps have corroded, and the internal diameter has been reduced by the products of that corrosion. Consequently, the rod is being 'grabbed' by the end cap. As UP pressure is nearer 3,000psi, and it's being applied to the full surface area of the piston, the ram is able to extend. However, the DOWN pressure is much less, about half, and is applied to the surface area of the piston LESS the area taken by the rod where it joins the piston. The nett result is that there is less than half the force retracting the ram than extending it.

The fix is not to difficult, or expensive. Simply replace the end caps (and their associated seals)... Many people just clean up the caps, but it doesn't last long, the anodized surface has been compromised, so it will continue to corrode.... Easier and more of a long-term fix to just replace them and be done with it.

Chris.....

Should I just buy the end caps or a "rebuild kit"

 

[achris]

That particular era had quite a few different rams. If you can post a photo of the rams, and the casting numbers on them, I can work out which parts you need. The caps don't come with the seals, so you need the caps and the seal kits. Also, if you can measure the cap OD, we're looking for either 2.081" or 1.89"... Small difference I know, but that'swhat we have.

The casting numbers are going to be #14035 and #14034 or #98703 and #98704....

 

[Marinemp]

That particular era had quite a few different rams. If you can post a photo of the rams, and the casting numbers on them, I can work out which parts you need. The caps don't come with the seals, so you need the caps and the seal kits. Also, if you can measure the cap OD, we're looking for either 2.081" or 1.89"... Small difference I know, but that'swhat we have.

The casting numbers are going to be #14035 and #14034 or #98703 and #98704....

Ok so I removed the rams and I can freely spin the ram and move it in and out completely on both of them is this still a ram issue ?

 

[Fishermark]

Does the outdrive itself move freely up and down with the trim cylinders removed? I know it is heavy - but are you able to lift it without it binding?

 

[wahlejim]

If the outdrive moves freely unhooked from the rams, then it is either a ram issue, reverse lock valve issue, valve control issue, or pump issue. Based on the symptoms you are describing, I would replace the end caps and rebuild the rams with new seals. Also, adjust the reverse lock valve.

 

[Marinemp]

If the outdrive moves freely unhooked from the rams, then it is either a ram issue, reverse lock valve issue, valve control issue, or pump issue. Based on the symptoms you are describing, I would replace the end caps and rebuild the rams with new seals. Also, adjust the reverse lock valve.

Both the out drive and the rams move freely I can lift and lower the out drive and I can depress and extend the ram by hand easily ... but when even with the outdrive not attached to the ram the pump will not retract the ram like it's still binding even though I can move it by hand ??

 

[wahlejim]

I am not the most knowledgeable person in this forum on the trim rams, I can only speak from my experience with these older types of rams, but it seems you have an internal leak in your rams. There are seals and check valves inside when you push the down button that direct fluid back into the pump. If those seals or check valves are failing, fluid just kind of circulates inside the ram and doesn't go back into the reservoir unless more force is applied downward on the ram.

I had the same situation occur in my system. I could 'force' the outdrive down by having someone press the down button and I would stand on the outdrive to get it within safe operating range. Then I could only trim down while in forward gear as the force from the prop would make the drive go down. I changed the seals and adjusted my reverse lock valve and all is well.

Just a side note on the cause of mine, and I am only mentioning this because it is a new to you boat. My cause was hitting a sandbar with my outdrive, forcing the outdrive up ad forcing fluid pass the seals and valves. From my research, I found that the reverse lock valve on these older systems is designed to give way when hitting an obstruction, allowing fluid back into the rams so the rams can extend out. But since the fluid goes the opposite direction in the down system than it is designed to do, I believe that is what caused my damaged rams. After the occurrence, I inspected my transom (tried to tighten mounting bolts to see if they were jogged loose and looked for cracks inside and out) and performed a pressure test on my outdrive and they all checked out fine. It may be worth checking these items on your boat as well just for peace of mind.

 

[kenny nunez]

As in the above post if the rams retract almost all the way and stop about 2" from fully retracted then there is an "O" ring blown out in the extreme front of the ram. A seal kit will have all the "O" rings.
If the drive will not go down and not move from full up then there is a check valve out of adjustment in the valve body. To adjust it takes a gauge kit which is a Mercruiser item and part of a test kit. Trying to adjust without the gauge kit could cause the rams to split. If this is the problem you can probably purchase a new valve block with the seals for your model. 2 fittings and 4 1/4" 28 bolts.