Prestolite tim pump valve body assembly - a bit help anybody?

Discussion in 'Sterndrives' started by Nidza, May 26, 2017.

  1. Nidza
    Joined: Nov 2016
    Posts: 77
    Likes: 4, Points: 8, Legacy Rep: 10
    Location: Belgrade, Serbia

    Nidza Junior Member

    Hello,

    I have disassembled valve body of Prestolite trim pump (type without control valve and without manual release valve), and I know most of parts where should be positioned to assemble it again, but I am not sure of two smaller springs in which place should which one go? Here are the photos so my question will be clear after that:
    001.jpg

    002.jpg

    Problem is that two smaller springs are almost the same, except the length and both can fit in both holes (one hole above squared "floater" and the other above insert next to the squared floater).

    Does anybody know which of these two smaller springs should go in which hole? It is all about the limiting pressures, but all the shop manuals I have found about Prestolite hydraulics are not clear and detailed enough and on some scanned diagrams it is not visible at all. The drive will probably work anyway, but if interchanged, limiting pressures will be wrong which could be hazardous to equipment. One of these is used as protection if the drive is fully UP and pump is still pumping oil, and for the other was not really clear to me, but which is which could help because it would be clear which one should be set for higher pressure. Here is the link to document which explains hydraulic circuits (figures 2 and 7 and description text on pages 540):

    https://web.statler.wvu.edu/~mathews/boat/pdf/manual/Chapter Eighteen.PDF

    One note, on diagrams in latter document, reverse lock valve is shown and I do not have this in my system, but the drive is locked in its position when not trimming/tilting no matter if it is in froward or reverse. Outdrive is SternPowr.

    Thank you in advance for your answers!

    Nidza
     
  2. Nidza
    Joined: Nov 2016
    Posts: 77
    Likes: 4, Points: 8, Legacy Rep: 10
    Location: Belgrade, Serbia

    Nidza Junior Member

    I have solved it!

    When reassembling I have tried both options and only one was possible - Longer of two smaller springs goes above the squared "floater", otherwise the pressure setting screw above squared floater would come to the end position without squeezing the spring at all.

    Everything works fine now.
     
  3. Nidza
    Joined: Nov 2016
    Posts: 77
    Likes: 4, Points: 8, Legacy Rep: 10
    Location: Belgrade, Serbia

    Nidza Junior Member

    Stil need help or opinions on drive trim slipping issue (going down by itself or up when in reverse). That is why I have disassenbled and reassembled the pump and cleaned it altghough it was not that dirty. And that did help, but for about one month maybe.

    My question is:
    Would you consider that this is the issue of dirt since mentioned procedure did help or you would consider that valve balls and seats are not good any more? If the latter, do you know where those could be 'fixed' if possible or the best solution is changing the pump?
    Thanks
     
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