exhaust flappers

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

  1. Loyd Dinneen

    Loyd Dinneen Member

    265
    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 Active Member

    493
    Oct 22, 2007
    clifton nj
    420 da
    454
    A 240 with twin big blocks -that must fly-----
     
  3. Loyd Dinneen

    Loyd Dinneen Member

    265
    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

    265
    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

    246
    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

    300
    Sep 15, 2014
    Northern BC
    1980 245 SDC
    1984 18' Valco sled
    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

    222
    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

    265
    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.
     
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  11. Soulshine

    Soulshine Active Member

    222
    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

    246
    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
     
  13. Loyd Dinneen

    Loyd Dinneen Member

    265
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Just looked on Ebay and you can get a 16 ft endoscope for 9.00 and on up and it works on your smart phone,computer, and tv. I ordered one for 19.00 that uses a wifi to send signals to your I phone, and a 16 ft cord. I plan on putting it down thru the riser exhaust to make sure there is no shutter parts there before I install new shutters, I don't want to have to take it all apart again.
     
    Handsome Transom likes this.
  14. Loyd Dinneen

    Loyd Dinneen Member

    265
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Well I have both risers off both the engines and one of the risers is full of holes where the long bolts go thru so I will be replacing it. And the port shutter is missing also just the bar is there, next big question is how do you remove the bar? The exhaust pipe has what looks like a long bracket running down the inside on the pipe and is about 3 inches long and looks like a spring action at the bottom. I tried to push in on that area that looked like it might release the bar but can't get enough leverage, most likely some type of tool is suppose to be used. This is a 1977 mercruiser 470. There was a listing on another forum that showed a picture of it but I'm having a hard time finding it. Has anyone out there ever changed out this type of shutter? Need Help.
     
  15. Loyd Dinneen

    Loyd Dinneen Member

    265
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I think I might of figured out the shutter direction from a picture. I have installed one of the shutters on the starboard engine and it seemed to fit ok there is a gap on the ends of about 1/4" but the flap seems to move freely. I have it all back together and will test the engine tomorrow. The question I have is there suppose to be a little gap, I can see where the shutter would still stop the influx of a wave of water if it should come in as there is that hinged tension back toward the engine. How about some feedback on this.
     
  16. Handsome Transom

    Handsome Transom Active Member GOLD Sponsor

    246
    Jan 26, 2018
    Penetanguishene Ontario Canada
    1989 SeaRay Sundancer 268 454 Bravo
    454 Mercruiser bravo drive
    It would seem you have it as long as it is installed so pressure from the exhaust will push it open and it will close off when water comes up towards the engine the little gap I think is normal . I didn't get a pic of my new on since I did mine with the boat in water and that part is slightly below water level so I had to put the lower exhaust boot back on quickly . Good luck with the engine test tomorrow.
     
  17. Loyd Dinneen

    Loyd Dinneen Member

    265
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Thanks for your feedback and support.
     
    Last edited: Oct 5, 2018

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