Muffler & Exhaust Mods
Since both the FSII and the MKIII are based at a
strip immediately next to a subdivision, we wanted them as quiet
as possible, so both have intake silencers and after mufflers.
Since I am aware of several people who have experienced various
Rotax exhaust pipe failures over the years, such as cracking and
splitting, it was determined that locating the muffler in the
normal position off the side of the cylinder head was not an acceptable
option. IMO, having it way out and up like that contributes to
it being shaken about more vigorously. The closer you can get
it to the centerline of the engine, the less it gets thrashed
around. So it got located next to the engine and tied to the block
and the motor mount bracket.
Notice the heat shield below the muffler, this is
to keep the muffler from giving the Dacron a shrinking experience
that Stits never intended. It works well, the wing stays cool.
It is located by welded brackets at the front and back of the
muffler, the silver strap is the stock strap for the Rotax after
muffler, which runs alongside of the main muffler, & alongside
the muffler mounting brackets, keeping the inertial mass of the
muffler as close to the engine centerline as possible, once again
reducing stress on the various portions of sheet metal. Muffler
shock mounts are our usual Auto Zone muffler rubber hanger bits,
they have proven themselves well. We also hold the ball joints
snugly together using 5/16" spring loaded bolts instead of
the standard Rotax spring system, thus no danger of spring bits
going through the prop.
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