FWC Ranger 33

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  • Bsavulis
    Member
    • Jul 2017
    • 1

    FWC Ranger 33

    Hey all,
    I have a Ranger 33(1978, original A4) that is new to me this spring, MMI FRESH WATER COOLED and MMI ELECTRONIC IGNITION. The boat has had a few owners since the system was first installed. I have been having all kinds of issues getting the raw water side to pump, I installed a new impeller, faced the sealing surfaces, install a new oring, just to make sure there were no air leaks. When I pulled the pump I noticed that the system has 3/4 hose on many of the 5/8 barbs. I will address this issue this weekend by replacing all the hoses. My question is, should there be a "foot valve" / "check valve" in the raw water supply hose either before or after the strainer? I did not see any hint of one in the drawings on this website, but I thought I read somewhere that there was supposed to be. Any info you can provide is greatly appreciated!

    Brian
  • tenders
    Afourian MVP
    • May 2007
    • 1440

    #2
    There probably isn't supposed to be any restrictive valve at all in the raw water system, except for the seacock just inside the hull.

    Seems like you need to validate whether the pump is pumping properly, or whether something inside the cooling system is restricting flow. Disconnect the pump at the outlet, direct the outlet overboard or somewhere manageable, run the engine, and see what happens. You should be deluged with water. If you aren't, and you've done all this to the pump, I can only think of a few problems: the intake may be plugged, the impeller might be the wrong size for the pump and leaking water within the chamber, or the "shoe" in the body of the pump that compresses the vanes of the impeller as it spins is worn and isn't providing compression.

    If the pump is working then you probably have a restriction inside the cooling system. Usual Suspect #1 is a piece of an old impeller that broke off and was pushed in somewhere inconvenient. Usual Suspect #2 is rust chunks or flakes that broke off and lodged in a totally different set of inconvenient places. Sometimes backflushing the engine can send them out from whence they came, but don't do that with a lot of pressure (ie, don't use city water pressure) - that's too much of a good thing.

    Comment

    • JOHN COOKSON
      Afourian MVP, Professor Emeritus
      • Nov 2008
      • 3500

      #3
      When you replace the hoses and check to be sure the intake is clear try priming the pump. The pump should self prime but as pumps wear a bit sometimes a prime is needed to get the pump working.

      TRUE GRIT

      Comment

      • thatch
        Afourian MVP
        • Dec 2009
        • 1080

        #4
        Brian, I'll go ahead and say it, welcome to the forum. You will not find another place to go that will help you more with your A4 questions than here. You had mentioned having some 3/4" hoses on your water intake. If there is the slightest air leak in that part of the system, it will not pump water. All of the info so far is good so, take it one step at a time and we'll get you through it.
        tom

        Comment

        • JimG
          Senior Member
          • Mar 2005
          • 123

          #5
          I have a sea water cooled A4 in my R33, and every time I have a cooling problem, it turns out to be algae blocking the thru-hull fitting. I keep a test tube brush next to the thru hull so I can disconnect the hose and confirm I get a geyser. Maybe the location is just in a sweet spot for plant growth.
          S/V Latis
          Brookings, OR
          Ranger 33

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