Drive Trim Stuck 280 Sundance

[280grappler]

Using my boat for the first time in months, the drive trim on both drives seemed to be (was) stuck at about 3/4 "full up" on the gauges. I couldn't get the hydraulics to lower it with the control switches on the throttle. Took the boat out the marina entrance channel, and was churning up quite a bit of water, indicating that the reading was indeed correct. Once I got out to where I could run, I decided to go ahead and power up to see what happened. After pushing the throttles up to 3000 + rpm, I was suddenly able to get the drives to lower, and after that they seemed to be responsive to the control switches.

Anyone have an idea of why I had the original non-responsive condition? My dockhand proposed that its possible an air bubble had affected the hydraulics. I'm looking for understanding and any suggestions of how to avoid in the future. Thanks.

 

[cfd95]

Can't be an air bubble.
Each drive has its own pump to raise and lower.
Sounds like an electrical issue with the system.

 

[280grappler]

Ok. I agree that two separate systems suggests no air bubble.

I think I recall that there is advice against storage with the drives in the "up " or partially up posiion because they can become "frozen", but I'm not sure I'm remembering right, and I don't have an understanding of what would cause that.

 

[jason78]

As to the original problem, if you have the means to get the boat out of the water, that would probably be the best way to troubleshoot. Have a friend work the controls and watch what the drives do. It's hard to know what the drives are really doing in the water because the trim indicators are notoriously inaccurate.

I think I recall that there is advice against storage with the drives in the "up " or partially up posiion because they can become "frozen", but I'm not sure I'm remembering right, and I don't have an understanding of what would cause that.

The reason it is not recommended to store with the drives up is that it keeps the bellows in a stretched state which could accelerate them wearing out. Sometimes that cant be avoided if you are in a dry stack.

 

[barros1389]

hi-

It could be that the pucks got water in them. On my pervious boat, I recall that the drive would trim sometimes other times not. Once I switched the pucks, all was fine. It's a bad design and Mercury hasn't redesigned them.

 

[Bucit]

I would say look at the seals on the trim rams. They may be about to go and causing them to freeze up on the shaft. You can take a semi abrasive scrub pad or wet sand the ram. Spray some PB Blaster on it and let it sit. Wipe it down and spray some lubricant on it and run it up and down. I would always store the boat with them in the down position.