Sterndrive unit won't go down

Gunn

Gunn

Well-Known Member
TECHNICAL Contributor
Oct 4, 2006
2,335
Potomac River - MD
Boat Info
2003 280DA and 1995 Sea Ray 175
Engines
Twin 4.3l and 3.0l, all w/ AlphaI GenII drives
My sterndrive units were in the trailer position for some time. Today we went to take the boat out and I can not get the port sterndrive unit to travel downward. The starboard unit works fine.

When I move the port trim switch down, I can hear the trim pump running as it does when it's traveling. But it won't budge. If I move the switch to the up position, the pump does not operate, as it should.

If I hit the trailer switch to move the drives up, I can see the port unit barely budge and the motor loads up...which makes sense since it's at the up limit. But when pressing the switch down, it doesn't even budge. I tried to push on the unit while hanging over the swim platform while my wife operated the switch thinking that makes it's just plain stuck :)huh:) but that didn't help.

I checked the fluid levels in the pumps and though they are about an inch from the top, they are both the same, and the starboard side is working fine. I can run out and get some more fluid, but I don't think that's the issue...then again, maybe it is? I wonder how far from the top the fluid needs to be?

So, the switch seems to be fine, the motor seems to be fine. What else could I check or do?

Thanks,

Tom
 
Last edited:
A misadjusted trim sensor on the drive can cause the drive not to operate in one direction or another. Check the sensor and see if it moved. Otherwise, check your connections on the pump and at the switch.

Doug
 
With the drive all the way up in the "trailer" position the rams on the outdrive would be extended all the way. If you fill the reservoir to the top when the outdrive goes down it will have no where to send the hydraylic fluid in the rams and will most likely over flow. I know some hydraulic fluids will eat the paint off of a car, I'd hate to see what it could do on the inside of a bilge!
 
douglee25 said:
A misadjusted trim sensor on the drive can cause the drive not to operate in one direction or another. Check the sensor and see if it moved. Otherwise, check your connections on the pump and at the switch.

Doug
Click to expand...

Tom states the pump operates from the downward selection of the trim switch. This tells us the electrical circuit is complete. He also states the pump loads up when hitting the trailer switch. This tells us there is plenty of fluid, hydraulically the system is tight in the up mode and the pump is capable of making pressure.

Since Tom didn't say the pump loads up in the downward mode: I'm thinking the drive is not binding or hung up.

Tom: your problem to me sounds like some sorta flow check valve. There maybe a relief on the side of the pump body you could pull or you may have to pull the pump assembly and see what’s up.
 
I don't think it's the sensor first because I didn't mess with it. Also because it seems to be acting correctly; up trim won't work because the sensor says its all the way up, down trim button will operate. The connections all seem to be OK.

Good point on the reservoir level. So that must rule out the fluid level. Great.

I found online that they may be stuck due to lubrication and a press may get them going again. I took my kayak out and floated up under the boat (it's on a lift) and a bar clamp on each cylinder and tightened it. Pulsed the trim down switch and it would move about 1/16" inch. Tightened the clamps and repeated. I was hoping the pressure would just unstick the rams in the cylinders and then I'd be good to go. But that's not what's happening. I came in for a break as my hands are hurting from tightening the clamps. :huh: It is moving but painfully slow.

So I'm still troubleshooting for the problem...
 
Tom: by loosing the lines at the pump, the weight of the drive may bring it down. This would tell you if you problem is on the cylinder end or pump end. Keep in mind, one line should seep oil and the other will draw air in. If the lines can be reversed this may get it down anyways.
 
Sounds like a possible stuck solenoid in the pump/solenoid body. if you can get to it tap slightly with a small hammer on the solenoid body and then try it. If possible, have somebody work the switch while you are tapping.
 
Thanks for the great tips. Just came in and was able to get it into the full down position. Still don't know what is wrong, so here are some more clues.

I went back out and first removed one of the cylinder ends from the unit. Tried the switch. No movement. Then I swapped and took off the other cylinder. No movement. I would have thought I could figure out which cylinder was stuck with this method, but...maybe they both were?

So then I got a large ratchet strap and wrapped it around the lift I-beam crossmember and the lower unit. Ratcheted it tight and hit the switch. It would come down a 1/4" or so, until the strap pressure was released. Did this about 8 times or so and then it moved on it's own quite a ways (through 1/2 its travel or so) until just above the operating limit range where it stalled out (pump still operating). I used the strap again and pulsed it 3 or 4 times and then it moved on it's own again until it bottomed out.

In all of this time, anytime we hit the up switch on the throttle (once in operating range) or the trailer up switch, it would go up nicely, quickly and normally. But when it was able to go down itself, it was very slow. Slower than the starboard unit which seems to be working just fine.

So...rebuild/replace both cylinders or is it a pump issue maybe?

Thanks again everyone!

Tom
 
I think the idea of a stuck solenoid sound like the most probable cause at this point. BTW, have you greased your pivot bearings lately?
 
I guess I misunderstood your initial description. I wasn't aware that the drive was already in the full 'up' position. Like Ron said, it's probably not the sensor.

If you crack the hose when the outdrive is in the up position, can you easily lower the drive with just a little assistance from a helper? This would tell you if the rams or pivot bearings are binding. If there's no issue, then it must be with the pump and solenoids.

Doug
 
My outdrive did the same thing last year. It would not go down no matter what I did. Now my canoe is in fresh water so maybe not apple to apples but here goes. It seemed like the drive was air bound from sitting all winter in the up position. Even though the cylinders were at the top of the stroke, I filled the pump tank and began working the drive up and down until full stroke was achieved. I put a rag under the pump to catch any that came out however nothing did and when I was done cycling the drive the oil was at the correct level.

Just what happened to me hope you get it sorted out.
 
Is there enough "slack" in the lines at the pumps" to switch sides (starboard pump to port drive)? This would eliminate the pump, solenoid and the lines themselves.

Any chance the line has a blockage? Just thinking out loud here really.
 
Thanks for all the help. Thinking out loud is much appreciated! Since I was able to get the drive down with some manual help as mentioned, we were able to successfully get the boat to a ramp, loaded and is not at home on the trailer. So NOW I can do my spring maintenance...I'm way behind schedule. Now it's much easier to diagnose and fix this drive issue; just one more thing to add to the list.

There isn't enough slack in the lines of the pump as one is on each side he boat. But that's an idea, if I have to try that.

With a stuck solenoid, I'm guessing the trim pump would sound like it's operating, but just won't like in my symptoms? I had to replace a solenoid on my other boat but that was because I couldn't even hear a thing when I engaged the up trim switch.

Tom
 
Tom: The solenoids simple run the motor. Since the motor ran in both directions, it's safe to say the solenoids and all other electrical components were working.

The cylinders are double acting (push/pull). Since the motor ran in down position, but you did not hear it load up, you were not making pressure to push the cylinder rods in.

On the sides of the pump you should see two valves. About a (7/8?) head size. One of these were most likely hung up. Pull them out and have a close look at them. If you see no signs of things like cylinder seal packing in them, change the oil and call it a stuck valve or air locked as "OldSchool" mentioned.... just my 0.02
 
BonBini said:
The cylinders are double acting (push/pull). Since the motor ran in down position, but you did not hear it load up, you were not making pressure to push the cylinder rods in.

On the sides of the pump you should see two valves. About a (7/8?) head size. One of these were most likely hung up. Pull them out and have a close look at them. If you see no signs of things like cylinder seal packing in them, change the oil and call it a stuck valve or air locked as "OldSchool" mentioned.... just my 0.02
Click to expand...

Yes, you're right. Motor ran but not enough pressure to move them. And then when I did get it to move, it was slow. Seems consistent.

I'll check the valves, thanks!

Tom
 
Just that if the pump coupling or something else related to the pump itself is the issue, I think the drive would not go either way (especially not up, in which case the pump has to push against the weight of the drive).
 
You must log in or register to reply here.

Forum statistics

Threads
113,172
Messages
1,427,857
Members
61,086
Latest member
MrWebster
Back
Top