Need help understanding 496 Mag HO drain actuator assembly

Discussion in 'Sport Boats' started by Old Man In The Sea Ray, Jan 26, 2022.

  1. Old Man In The Sea Ray

    Old Man In The Sea Ray Member SILVER Sponsor

    39
    Dec 15, 2021
    Sarasota
    2003 Sea Ray Sundeck w/496 HO Bravo III
    496 HO Mercruiser w/B3 drive
    Greetings,
    Having recently replaced my raw water impeller and flushed the system, I decided to add a thru hull sea water scoop, strainer, and a flushing tee. I'll abandon and plug the hose from the outdrive. Midway between the pump and transom I run into this:
    upload_2022-1-26_19-29-41.jpeg
    Here's my confusion. The red hose (sea water in) goes thru this device and into the pump. It looks like a tee comes out of the bottom into the black hose (sea water return). Please explain the operation and function of this actuator.
    TIA
    Russ
     
  2. techmitch

    techmitch Well-Known Member PLATINUM Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    Can you post the parts list that goes with those #s?
    Where does #9 go and what size/type of hose is it?
     
  3. Old Man In The Sea Ray

    Old Man In The Sea Ray Member SILVER Sponsor

    39
    Dec 15, 2021
    Sarasota
    2003 Sea Ray Sundeck w/496 HO Bravo III
    496 HO Mercruiser w/B3 drive
  4. blaster

    blaster Well-Known Member

    May 23, 2011
    potomac river
    2010 sea ray 205 sport
    F-250 CCLB 6.2 4x4 3.73 rear.
    Mercruiser 4.3 mpi alpha 1.62
  5. paulswagelock

    paulswagelock Well-Known Member

    Oct 25, 2010
    pa
    2018 SDX 270 OB 300 Verado
    Verado 300
    When you pump it up with air, the actuator slides positions and the sea water drains to the bilge for freeze protection. Release the air and it goes back to normal flow path. So the small line goes to the air pump on the front port side of the motor. The bottom remains open to the bilge.
     
    Last edited: Jan 27, 2022
  6. Arminius

    Arminius Active Member

    701
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    Does the air pump shown in the "winterization" section of manual have any other function?
     
  7. paulswagelock

    paulswagelock Well-Known Member

    Oct 25, 2010
    pa
    2018 SDX 270 OB 300 Verado
    Verado 300
    Not really. On the 496 it also pumps open the collector on the lower port front of the motor. It is a gray plastic piece with multiple water hoses on it. It also pumps open and allows sea water to drain out of the block and other passages for extended cold weather operation.
     

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