exhaust flappers

Discussion in 'General Maintenance/Repair Questions' started by Loyd Dinneen, Sep 11, 2018.

  1. Loyd Dinneen

    Loyd Dinneen Member

    240
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I just replaced a exhaust riser on the stbd engine and when I looked down in the pipe I didn't see any flaps does the mercruiser 1977 470 have them? I see a bar going across but no flap.
     
    Last edited: Sep 11, 2018
  2. Sublimetime

    Sublimetime Member

    445
    Oct 22, 2007
    clifton nj
    420 da
    454
    A 240 with twin big blocks -that must fly-----
     
  3. Loyd Dinneen

    Loyd Dinneen Member

    240
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Don't know yet haven't had a chance to open it up been too busy fixing stuff that keeps breaking or needs repaired. Boat was kind of abused a bit. Putting in a couple of alternator kits next waiting for it to cool off a bit, latest thing to break while still parked in front.
     
  4. dvx216

    dvx216 Well-Known Member SILVER Sponsor

    Feb 1, 2012
    orrville,ohio
    2000 310 sundancer 5.7 vdrives






















    n/a
    twin 5.7 300 Hp. V drives
    the bar is whats left of the flaps
     
    Handsome Transom likes this.
  5. Loyd Dinneen

    Loyd Dinneen Member

    240
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I have looked and haven't seen where they are mentioned.
     
  6. Handsome Transom

    Handsome Transom Active Member GOLD Sponsor

    217
    Jan 26, 2018
    Penetanguishene Ontario Canada
    1989 SeaRay Sundancer 268 454 Bravo
    454 Mercruiser bravo drive
    Pius 1 on that's what us left of the butterfly valves.
     
  7. dvx216

    dvx216 Well-Known Member SILVER Sponsor

    Feb 1, 2012
    orrville,ohio
    2000 310 sundancer 5.7 vdrives






















    n/a
    twin 5.7 300 Hp. V drives
    the new and improved part will replace the old style flap
     
  8. Thornton69

    Thornton69 Active Member

    281
    Sep 15, 2014
    Northern BC
    1980 24.5' SR custom hardtop
    1984 18' Valco sled
    1984 20' Alicraft- sold
    5.7 260 Merc/ Bravo 2
    Evanrude 115/80 jet
    The 470 was a 170hp 4cyl last I checked.
     
    Handsome Transom likes this.
  9. Soulshine

    Soulshine Active Member

    219
    Sep 25, 2016
    Seneca Lake, NY
    '83 SRV 360 Express
    Twin Merc. 454
    I’d want to know if the flaps were down in the bottom of the pipe.

    The flaps or melted fragments of them down there will obstruct exhaust flow out through the transom and cause a hard to find over heat situation.

    You can see the place where they’d land with the drive off or fish around from above with a hooked wire.
     
    Handsome Transom likes this.
  10. Loyd Dinneen

    Loyd Dinneen Member

    240
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    After I get the charging system squared away I will take the exhaust elbow off again and look down in exhaust pipe and see if theres some parts and pieces. Perhaps something else to fix will have a look at the port side too when I get the time. Didn't see anything when I had the drives off and changed out the bellows. Temp wise the engines are now running at about 160 on muffs after changing out the stbd elbow,flushing,cleaning the heat exchanger,new thermostats,and installing new coolant at 50/50.
     
    Handsome Transom likes this.
  11. Soulshine

    Soulshine Active Member

    219
    Sep 25, 2016
    Seneca Lake, NY
    '83 SRV 360 Express
    Twin Merc. 454
    All good things, but the muffs can give you a false sense of security since they deliver more water than the raw water pump does.
     
    Handsome Transom likes this.
  12. Handsome Transom

    Handsome Transom Active Member GOLD Sponsor

    217
    Jan 26, 2018
    Penetanguishene Ontario Canada
    1989 SeaRay Sundancer 268 454 Bravo
    454 Mercruiser bravo drive
    Water proof endoscope for a smartphone is around 100 bucks . I'm asking Santa for one this year lots if times I want to see things where my fat head can't fit . It's always a chore with new used boats but getting a thorough shakedown done will give you peace of mind and avoid preventable problems from costing you much more. It feels good heading out when you know you have everything you can taken care of. FFTP(fortune favours the prepared)
    Welcome and happy boating
    Dave
     

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