VP DPH-B drive will not tilt at 6 knots or higher

[Hosse]

First post
I have been looking for some answers for my problem with my DPH-B drive (on a 2007 VP D4 260 A/B engine). The problem is that I cant move my drive up or down during speeds over 6 knots. At 5 knots or lover the trim/tilt work perfect. When I speed up a bit, nothing happens when I try to trim it.

It seems like no one has heard of this problem before here in scandinavia. I find that strange, so therefore Im asking you nice guys a iBOATS

Any idea?

Best regards

 

[alldodge]

Howdy
Since it works at slower speeds and not at higher, your pump is not producing enough pressure, or its leaking down.

If you can raise the drive a bit more then needed, take off and it does not bleed down, then its not the cylinders or check valves. If the above is correct, need to put a pressure gauge on the trim pump to see what pressure the pump is outputting.

Do use a good gauge and high pressure lines. Pressure will be around 1400 psi (100 bar)

 

[Hosse]

Thanks AllDodge !
The Drive doesnt "bleed" at higher speeds. It looks like the drive stays at the exact point, as I have put it in at lower speeds, in higher speeds.

I will try to get a good gauge an messaure it my self then. 100 bar is a lot

 

[Hosse]

Some one has also said that there could be air in the system. I can't find any guide for a way to fix this myself. Any one here who has done this?

 

[alldodge]

Air bleeds out by it self with just running the cylinders in and out. If it did have air, then the drive would move as the load increased, air can be squeezed, oil can not

 

[Texasmark]

"The Drive doesnt "bleed" at higher speeds. It looks like the drive stays at the exact point, as I have put it in at lower speeds, in higher speeds."

Yes it is. It has a problem, leaking piston for one, or flow valve not sealing that releases at some differential pressure....5 knots worth of pressure...increased pressure just means increased leakage....could be as simple as low oil in the reservoir.....in Merc PTT systems the trim fluid, or ATF if red needs to be at the lop of the fill hole.....putting any more in will run out...then reinsert the plug. Oil should be clear. Max up and max down, up and down half a dozen times at 0 Klicks or on your trailer to bleed. Other wise time to replace some internal rubber.