Anyway to make Hardin “silent seal” flappers quieter?
08-29-2012, 05:15 PM
#11
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I just ran both my engines with the new tips with the internal flappers. In the engine compartment you can hear a rapping noise that comes and goes with the idle . I put a long screw driver up the tail pipe to hold the flappers open. The noise was not there when I ran it like this. It seems that with a good size cam the reversion slaps the rubber flapper against the steel frame in side the tail pipe and sounds like a rod knock. Hard to believe this could make that kind of noise. I am so relieved to know that it is the tail pipes and not the engine.
08-29-2012, 05:20 PM
#12
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Flappers
Can someone please video what this noise is that your hearing? We have sold virtually thousands of tips with this rubber silent seal designed flap. This flap is merely a rubber flap that lays against a support cage.We have not heard of these noises? In an effort to revisit this we went outside today and ran all versions of tips and video the findings. As you will see here and cannot duplicate the noise you are referencing? We were able to hear the "Tinking" noise of the metal flap but that's about it. Here's our findings while not an exact duplication of the boat in the water we are able to get right next to the tip and not duplicate any of your clacking/knocking noise?
http://www.youtube.com/watch?v=iDiDe...ature=youtu.be
Best Regards
http://www.youtube.com/watch?v=iDiDe...ature=youtu.be
Best Regards
Arthur McKeon
08-29-2012, 06:51 PM
#13
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Mine make a loud sound like an engine knock, until the water begins to flow thru the exhaust. THen they quiet down. I have the Hardin Extended slash cut tips with the internal flappers like pictured. It scared the hell out of me when I first fired it up, because I cahnge to the new tips in the offseason. So it was the first time firing it up for the season...... But once water came thru the exhaust they were quiet. Also the noise is only audible when I had the engine hatch open.
Last edited by low_psi; 08-29-2012 at 07:42 PM.
08-25-2014, 06:33 PM
#14
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Just installed the slip-on version and ran the motor without any noticeable change in tone. These were the perfect solution replacing the burnt out internals I had. Now that the housings are installed flap replacement will be a snap. Super happy, thought I would add this for anyone considering this product as this thread had me a bit worried before the install, no problems here?!
08-26-2014, 11:50 AM
#15
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http://www.youtube.com/watch?v=iDiDe...ature=youtu.be We cannot determine this noise and would love for someone to add a video of this
noise?
08-26-2014, 12:13 PM
#16
When I was testing my engine on a test stand with just open marine headers and no tips, I was amazed at how hard the exhaust pulse sucked back into the pipe. I held a piece a paper up to the pipe and it tried to suck it right out of my hand. This was with a fairly mild 226* 230* cam on a 114* LSA. The engine did have the longer 4.25" stroke and aftermarket (AFR) heads that have a much better flowing exhaust port, so I am wondering if that had something to do with it. I was actually getting water reversion back into the primaries, but this was for the most part eliminated when I installed a set of mufflers with Salisbury type flappers. The flappers acted like an anti-reversion valve, moderating the back-pulse. I suspect a similar dynamic was occurring with these engines that previous posters mentioned. The flappers may actually be doing you a favor in preventing reversion to some degree. Certainly worth thinking about.
