<HTML><FONT FACE=arial,helvetica><FONT COLOR="#8000ff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">I have been having occasional problems with RPM and what seems like overheating on my YS-140-L. I have come to believe the problem is restriction in the muffler, but the muffler seems to be open and OK<BR>
The problem seems to have something to do with the prop size also. <BR>
Running a 15-1/2 x 13N rpm at about 8200 everything is fine, switched to a 16 x11 and running @ 8400 rpm and later in the flight the power back's off, I think it is heating up.<BR>
Yesterday I switched to a 16 x10 prop turning 8800 rpm and half way through the flight I heard a loud pop, After that the engine would not turn up. I landed and found that the Teflon coupler had split long ways about three inches long and had curled inward restricting the flow. This has happened on two different mufflers a Hatori and a Johnson that is shaped like the Hatori Has anyone run into this problem before? and what is the solution? Is there another Aluminum muffler that will work? I have another setup using a CF muffler and have not had problems with it even at 9000rpm with a 16 x11 prop but choke when I think of spending $175.00 for another muffler.<BR>
Buddy </FONT></HTML>