the Rotax Aircraft Engine Fan belt.
One of the most neglected areas of the Rotax
aircraft engine is the adjustment of the fan belt. One reason is
that it is difficult to get at in most installations - thus it is
ignored in preflight.
A simple way of making it easy to inspect the belt is to remove
one of the "EARS"
from the fan cover. I usually remove the one that is opposite the
exhaust that way I don't have to go over the exhaust to inspect
the belt. Use a knife or pair of wire cutters to clip the
"EAR" off just
below the reinforcing.
With the ear removed and the engine
TURNED OFF you can use
your - finger to reach in and check for fan belt tension and or
inspect for damage or wear.
An improperly tensioned or worn fan belt can result
in a loss of horsepower and overheating. A belt that is too tight
can result in incorrect ignition timing! Which could lead to
The Rotax maintenance
schedule suggests the belt be checked every 25 hours of use.
To adjust the belt to the proper 1/4" deflection at 5 lbs pressure
as per figure A use the Rotax fan wrench tool
876 - 357 and the socket wrench supplied in your tool kit part #
876-210 to remove the nut, lockwasher, fan, and fan protector.
To tighten the belt remove
shims from between the two fan halves. On new engines these shims
are placed behind the back fan pulley #8, on older model engines
they can be placed under the lockwasher.
When reinstalling the fan and
tightening the nut turn the fan over as you tighten down on the
nut, or you will catch the belt, which could damage it. Once you
have the nut snug use the fan wrench tool to lock the fan while
you torque the nut to 40 ft. lbs.
|Fan wrench tool
|Fan for 503 Rotax DCDI
|Fan belt for 503 Rotax