exhaust flappers

L

Loyd Dinneen

Active Member
Jul 29, 2017
484
Las Vegas
Boat Info
1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
Engines
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.
 
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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.
 
I have looked and haven't seen where they are mentioned.
 
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.
 
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.
 
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
 
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.
 
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.
 
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.
 
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.
 
Thanks for your feedback and support.
 
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