Volvo Penta DPH shift stuck in neutral

[Pet_1]

Hello
I have had this issue twice now after not using the boat for about 4-5 weeks where one of the drives would not go into gear. I think this has happened once to each drive.
After trouble shooting the problem I found it was the drives shifting piston that would not move caused by a build up of calcium/scale between the piston and the control housing. After removing the scale all is well. my questions are....
Is this normal ?
Is there something wrong ?
Does this area require any work as part of a normal service ?
Would a coat of antifouling help ?
At present I have covered with as much grease as I can but can't see this lasting to long.
Your help and experiences would be appreciated.

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744790-44-6274.aspx

 

[[2068]]

Definitely no antifoul!

Is there water leaking from somewhere onto the piston, from above?

It’s not a service item, other than that changing the shift cable a newer low-friction one is a good idea if it starts to become stiff. Cheaper than a new actuator. A lot cheaper than a new PCU.

 

[Pet_1]

Hello Flowerpower
I have added a link to an exploded view.
The piston and controller are under a "U" shaped cowling at the top of the drive and are below the water line.
Why no anti-fouling.

 

[volvopaul]

Hello
I have had this issue twice now after not using the boat for about 4-5 weeks where one of the drives would not go into gear. I think this has happened once to each drive.
After trouble shooting the problem I found it was the drives shifting piston that would not move caused by a build up of calcium/scale between the piston and the control housing. After removing the scale all is well. my questions are....
Is this normal ?
Is there something wrong ?
Does this area require any work as part of a normal service ?
Would a coat of antifouling help ?
At present I have covered with as much grease as I can but can't see this lasting to long.
Your help and experiences would be appreciated.

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744790-44-6274.aspx

The shift piston needs to be clean of limescale.

If you have DPH A drive there was an update on the shift actuator , the actuator had some issue , I’d say that’s your problem if it’s sticking .
Also the bracket bolted to the drive case that supports the intermediate rod can bend throwing out the shift movement.
Change the cable to the Xact model.

 

[[2068]]

Hello Flowerpower
I have added a link to an exploded view.
The piston and controller are under a "U" shaped cowling at the top of the drive and are below the water line.
Why no anti-fouling.

Ahh, the underwater shift mechanism, I thought you were referring to the actuator.
As above, it could be that a buildup of scale is just too much friction including cable friction.
I'd definitely try a newer low friction cable.

 

[Pet_1]

Hi volvopaul
The actuators are good, movement is smooth. I replaced the bolt on bracket to both drives early this year as one had cracked, as the replacement part had been modified to make it stronger I replaced them on both drives. The cables were replaced 3 years ago and they move OK, I was planning to replace them next service.
The issue is definitely the build up of scale around the piston. Is there any thing I can coat the area with to stop the scale building up.

 

[jimmy_the_builder]

Hi volvopaul
The actuators are good, movement is smooth. I replaced the bolt on bracket to both drives early this year as one had cracked, as the replacement part had been modified to make it stronger I replaced them on both drives. The cables were replaced 3 years ago and they move OK, I was planning to replace them next service.
The issue is definitely the build up of scale around the piston. Is there any thing I can coat the area with to stop the scale building up.

I have early dph drives and I had to replace the selector assembly mechanism on both of them after one of them started to intermittently jam. The original part was superceded iirc. The problem with the selector assembly jamming is that it causes the actuator to burn itself out. The selector assembly itself is quite cheap so if your drives are early ones then I'd replace the selector assembly mechanism in both of them before it costs you an actuator.