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Western/Fisher pump "down" adjustment?

Discussion in 'Fisher Engineering Discussion' started by Raymond S., Nov 23, 2008.

  1. Raymond S.

    Raymond S. Senior Member
    Messages: 513

    I read on here somewhere about adjusting the speed that the blade drops on these pumps. I have a MMI with a western pump I believe. Anyway, it said there were two screws above the fill hole, which I found. It also said to take the top screw, bottom it out, and adjust it out to the desired speed to drop. Well I tried both screws and neither one did anything, it still drops like a rock. Am I doing something wrong or am I even heading in the right direction.

    Thanks in advance.:confused:
  2. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    We need to find out what pump you really have first.
  3. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,039

    try tightening your packing nut. I think I read the same thread not too long ago, but I also think that was on an instact. Does yours look like this...

  4. Raymond S.

    Raymond S. Senior Member
    Messages: 513

    No, sorry it is the InstaAct. It has the oval shaped filter on the end of the pickup not the round one. (found that out the hard way.)
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If it's an Insta-Act pump those two screws "right above the fill hole" are the pump pressure relief valve and the driver side crossover relief valve so its no wonder it didn't affect the drop speed any.

    Before you do anything else you need to reset BOTH of the screws/settings you disturbed in order to reestablish the correct pump and cross over pressure settings. :nono:

    The drop speed screw is on the top of the valve block right beside the motor. Should take a small straight screwdriver. If it's an older plow expect it to be corroded in place...may take some work to get it to turn.
  6. Raymond S.

    Raymond S. Senior Member
    Messages: 513

    I reset the screws back to the number of turns I turned them in. Is this an exact setting or simply 8 turns in = 8 turns out. I may be 1/2 turn off either way.

    The screw you are talking about, If I'm facing the front of the pump, it's on the RH side towards the front? I saw that one, almost like a set screw only with a flat screwdriver slot in the top.
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thats the one Raymond. :nod:
  8. Brian Simmons

    Brian Simmons PlowSite.com - Sponsor
    Messages: 196

    on the two that were misadjusted should be as follows - top hole is your crossover relief and should be backed out 1-1/2 - 1-3/4 turns and the bottom is your system pressure which should be 2 -1/2 turns out.

  9. Raymond S.

    Raymond S. Senior Member
    Messages: 513

    Thanks for the replies fellas. I will adjust the screws accordingly later on when I get home. What effect would it have if the screws were originally 4 complete turns out? Assuming Brian Simmons is correct w/ the 1 1/2 out etc...why would they have been set so far out. I suspect someone just set them that way in error?...
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Someone fooled with them who didn't know what they were doing at some point in the past possibly. The pump press really should be set with a pressure gage for the best accuracy.
  11. Raymond S.

    Raymond S. Senior Member
    Messages: 513

    I reset them tonight, and adjusted the other screw a touch. Works much better now. Thanks for all the help guys.:salute: