January 89
SERVICE BULLETIN
There
have been some instances where operators have been using 50 to I gas/oil
ratio mixes for the Rotax 185cc engine. These engines are used on the
Lazair Ultralight Aircraft. This is not advisable. In the original
configuration the factory recommended a 25 to I mixture.
However in the
Ultralight configuration a 30/35 to I is recommended - break-in and up to
10 hours of operation use a 30 to I mix ratio. After 10 hours a 35 to I is
fine. A high quality petroleum base two-cycle oil is recommended.
NOTE
using the larger Rotax engine oil mix ratio of 50 to I can and usually
does lead to early crankshaft seal failure. Leaks at these areas can lead
to lean fuel mixtures causing engine damage, and leaks at the mag side can
result in oil on the points thus causing an engine failure.
WARNING
- Propellers used other than the Bi-Plane type
Wooden
props (32 x 11) have stressed the P.T.O. end of the crankshaft to the point
of failure. However the time or point of operation of the failure cannot
at present be determined. We have experienced failure at as low as 20
hours and as high as 115 hours. This breakage can occur at the radius of
the P.T.O. end of the crank and will not cause loss of prop or personal
injury.
Breakage in the area immediately behind the prop hub results
in loss of the prop and prop hub assembly and could cause personal
injury. In conjunction with the Ministry Of Transport accident and lab
division, Rotax and Reg's Air Cooled Engines a new crankshaft
was developed that helps reduce the above problem from occurring.
The new
crankshaft is manufactured with
a completely new portion of the P.T.O. section. It consists of a thicker
portion of the hub area, locating keyway deleted, and a change of the radius
at the flywheel area.
To this date we have not had any failures with the
above combination of Heavy Duty Crankshaft, and the above mentioned
props. We have experienced failure of the combination of old crank
type and Bi-plane props at the 400 to 450 hours. Further information can
be obtained by phoning or contacting L'il Hustler Ultralight Aviation
THROTTLE KITS
Reg's
Air Cooled Engine1s Throttle kits are available. These are
complete kits using a self lubricating casing and a stainless steel
flexible cable. Benefits include long life, less cable sticking, easier to
synchronizing engines, some have been in service for five years with out
any problems. Complete kit for one engine) cost is $49.95(Canadian)
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