340 da vacumflush

Discussion in 'Sport Cruisers' started by Sam bevilacqua, May 19, 2019.

  1. Sam bevilacqua

    Sam bevilacqua New Member

    Sep 14, 2017
    2000 34 searay sundancer garmin
    7.4 mer
    vacumflush will not flush ,the pump will not stop, will not flush water.
  2. Express 390

    Express 390 Active Member

    Sep 14, 2018
    South Shore of Long Island NY
    1986 SeaRay 390 EC
    1993 SeaRay 290 DA single 7.4 /Bravo 2
    1992 SeaRay 230 DA 4.3LX Alfa drive
    Twin 454 Crusaders inboards 4 blades
    Need a little more info you step on the pedal does water go in and vacuum pump not stop? IF so you will need to replace the ball , gasket , and water inlet valve in the toilet its a kit.
  3. Boat Guy

    Boat Guy Well-Known Member

    So the bowl will overflow with water if you hold the pedal down?

    The hose seems blocked....What was put down it?
  4. wayne0

    wayne0 Active Member

    May 4, 2014
    Newburyport, Ma.
    2000 340 Sundancer
    Twin 7.4 ltr.V-drives
    Sounds like you are not building vacuum. Cracked bellows or a major leak in the system.
  5. KevinC

    KevinC Well-Known Member

    Feb 25, 2011
    Long Island, NY
    2004 340 Sundancer
    Twin 8.1 V-drives
    +1 If your pump does not stop then you probably are not building up a vacuum. That leads to a leak in the system. Could be something as simple as the seal around the ball in the head or something else like a leak in the line.

    There is also a pressure relief valve on the top of the tank that could leak.

  6. Korkie

    Korkie Active Member

    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags
    Bravo III Drives
    Was it working normally last year? Duckbills need changing. They get hard and crusty over the off season and will not seal. No seal -no vacuum. No vacuum - no flush. Same problem last season for me. Took out pump assembly and disassembled. Had the wife run to WM to get duckbills (need 4) while I cleaned unit up. New duckbills installed and problem solved. Some rubber gloves are an essential tool.
  7. KevinC

    KevinC Well-Known Member

    Feb 25, 2011
    Long Island, NY
    2004 340 Sundancer
    Twin 8.1 V-drives
    +1 - could also be something stuck in the duckbill not allowing them to close. That's a discussion to have with guests visiting the boat. We regularly inform our guests that basically nothing goes into the head that does not come out of you - except for a small amount of our special toilet paper ;)

  8. JustRight

    JustRight Active Member SILVER Sponsor

    Aug 4, 2013
    Seneca Lake, NY
    2005 Sea Ray 340 Sundancer
    1996 Renken 190 open bow
    1981 Chris Craft Catalina 350
    Twin 8.1 MPI inboards
    There’s a lot of parts (particularly dirty seals) and/or circumstances (i.e. a plugged waste line) that can occur in the vacuflush system that could create this situation. I would encourage you to do a search on the forum and gain an understanding of your system so you can troubleshoot it. My vacuflush is somewhat temperamental and, over the years, I have replaced all of the seals in the toilet and foot petal, but I have not had to replace the duckbills and would certainly hesitate prior to tearing into those before troubleshooting to identify potential other causes of the problem.
  9. Sublimetime

    Sublimetime Active Member

    Oct 22, 2007
    clifton nj
    420 da
    Duckbills are the number one cause of problems with the vacuflush. I would start with those as they are the cheapest part in the system, and you should have an idea of their condition before going any further.
  10. Benjamin Gray

    Benjamin Gray New Member

    Jun 19, 2019
    2005 Sea Ray Sundancer 260 (Sold)
    2002 Sea Ray Sundancer 340
    Twin v-drive 8.1
    Hey all had a sh*tty situation on our 2002 340 this morning. We slept on it last night with no issues. Woke up this morning and Wife used and flushed the head once, heard the pump build vacuum then shut off (took the usual 45 seconds or so) and 5 Minutes later it was my turn. I did my thing and gave a courtesy flush with good vacuum at which point no pump and no vacuum out of the blue. Yikes! not good. We proceeded to cycle everything off and on, the panel showed “power” but no empty, 1/4, 1/2, 3/4 or full indicators illuminated. We float over to the pump out and pulled a considerable amount of waste, when finished both the power and empty lights were illuminated, however the pump would not run to create vacuum no matter what we did. Any ideas? I’m a bit surprised that it would just die with no warning but hey anything is possible. Any thoughts would be greatly appreciated. TIA!
    Last edited: Sep 19, 2020

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