Sterndrive unit won't go down

[BonBini]

ah I see... You see the electric motor turns the pump clockwise for (say) lifting, then counter clockwise for (say) lowering. The two electric solenoids on the pump group make this happen. Only one is activated at a time. There is an up sol and a down sol.

The fluid will circulate through the cylinders in either direction depending which way the pump in turning.

The fluid needs to be locked in the system when the pump is not in use (so the drive wont drift down). this is don by the two little load check valves.

So lifting the drive till the cylinders dead head and motor labors, means motor works and system can make pressure. Lowering till the cylinders bottom out and motor labors means all is good in both directions.

Tom was good lifting, motor labored indicating good pressure.

Tom was not good lowering, motor did not labor indicating no pressure. Tom even went as far to have one cylinder off and the system would not even retract the cylinder rod.

Hope that sums up my thought process.

 

[Gunn]

Ron, you have summed up my symptoms exactly, thank you!

Even when I could get it to move downward, it was very slow in doing so.

So...still think a pump valve issue?

Also, I took a look in the Mercruiser service manul (#14) and it shows the pressure relief values on page 1C-20.

In the troubleshooting section titled "Sterndrive Unit Cannot Be Lowered From UP Position Or Lowers With Jerky Movements", it mentions possible issues:

• Air in trim system.
• Low oil level.
• Insufficient IN/DOWN pressure or shuttle valve stuck (pump adapter or pressure relief valve)
• Down pressure relief valve (6) has dirt particles under check ball. (valve kit)

So you're onto something, and all of these have been mentioned in this thread.

Tom

 

[techmitch]

"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."

"Insufficient IN/DOWN pressure or shuttle valve stuck (pump adapter or pressure relief valve)
Down pressure relief valve (6) has dirt particles under check ball. (valve kit)"

We have a pump/motor creating hydraulic pressure. A reservoir to draw fluid from and return it to. A valve body that determines which direction the fluid will travel.

Maybe You guys should help me understand this better.

 

[Steve Kasper]

Instead of pulling the lower unit, why can't you re locate the wiring above the water line.

 

[Bt Doctur]

If it was stored in the up position without relieving the pressure it could be stuck. A few ways,
have a weighted person stand on the drive .

reverse the hyd lines at the pump and use trailer

button to lower then reverse the hose connection at the pump

If the seals at the end of the ram are buldged outward the end caps squeezed the O rings from corrosion, new end caps will fit the problem

 

[Steve Kasper]

I kind of got on the wrong blog, my problem is the trim won't go up high enough. It goes down fine but only raises about 5 or 6 inches. I keep reading about a "trailer" switch or button but I can't seem to find one on my 1984 Sea Ray. I see the trim limit switch and I see that it is adjustable. I think I am going to play around with the setting to see what happens. Do you have any idea which way to turn the switch to get the lower unit to raise more?

 

[Steve Kasper]

Disregard, we located the"trailer" switch on the opposite side of the throttle control grip.