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Old Mar 06, 2013, 10:52 PM
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any benefit it to using the factory suppressor on a 4 stroke

during a bench test on my os 4 stroke the suppressor set screw came loose and blew the suppressor off, i noticed that the engine seems to run much smoother without it on or maybe it was just a increase in the exhaust noise, i didnt have the rpm gauge handy. does the suppressor help or hinder the engine? it seemed to respond more in rpm to adjusting the carb then when it was on. thats is also a small .30
thanks jeff
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Old Mar 06, 2013, 11:01 PM
datsunguy is offline
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What is a suppressor?
Old Mar 06, 2013, 11:11 PM
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the chamber at the end of the exhaust pipe
Last edited by jeff262; Mar 06, 2013 at 11:16 PM.
Old Mar 06, 2013, 11:14 PM
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The suppressor (aka muffler) will reduce both noise and power somewhat.
The engine will run fine without it in place, however, it is also a source of pressure for your fuel tank.
Old Mar 06, 2013, 11:53 PM
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Muffler is what I've always heard it called.
Old Mar 07, 2013, 12:23 AM
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Originally Posted by datsunguy View Post
What is a suppressor?
A dictator in some banana country ?
Old Mar 07, 2013, 06:57 AM
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Most four stroke engines run fine without a muffler on the end of the exhaust tube. But most flying clubs require a muffler for one to fly at their flying fields along with some sort of a maximum noise level based on measuring DB's. So you might have to have a muffler irrespective if the engine makes enough noise or not. Then most fellows have to provide "muffler pressure" to the vent line of the fuel tank in order to get the engine to run good too.
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Old Mar 07, 2013, 07:54 AM
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Jeff, if the engine really ran smoother after the silencer fell of it was likely due to running too rich and the loss of muffler pressure let it lean out and run smoother.
Old Mar 07, 2013, 04:52 PM
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Pretty good theory there, but it sounds like you adjusted the needle afterward, is that right?

I've flown a .40 four stroke with no muffler and it made less noise than most engines with mufflers. With no muffler pressure it would not run out a tank until I rigged up the tank as a uniflow and then it was good to the last drop.


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