O.S. Engines 91SX-H - Manual (Page 21)

ADJUSTING CHART
Open the Needle Valve 2 turns from the fully closed position.
Make sure that the Mixture Control Valve is at the factory setting. A
Start the engine
Warm up the engine
B
C
Observe the mixture condition while "floating" the model
Turn the Mixture
Control Screw
counter-clockwise
Idling OK
Turn the Mixture
Control Screw
clockwise
Lean mixture Rich mixture
D E F E
Observe the hovering mixture condition
Open the
Needle Valve
(Turn counter-clockwise)
Hovering OK
Lean mixture Rich mixture
J
H I
G
Close the
Needle Valve
(Turn clockwise)
Land the model
Idle for approx: 10 seconds, then reopen throttle to
observe transition ("Float" the model)
Turn the Mixture
Control Screw
counter-clockwise
Idling OK
Turn the Mixture
Control Screw
clockwise
Lean mixture Rich mixture
High Speed Flight
Open the
Needle Valve
(Turn counter-clockwise)
Lean mixture Rich mixture
L
M
Close the
Needle Valve
(Turn clockwise)
High Speed Flight OK
Fine tuning of hovering mixture
Turn the Needle Valve
2 or 3 clicks counter-
clockwise, or turn the
Mixture Control Screw
1-3 degrees counter-
clockwise. Adjust pitch
control characteristics.
Hovering OK
Response too sensitive
N
Response too slow
Adjustment completed
P Q O Q
Turn the Needle Valve
2 or 3 clicks clockwise,
or turn the Mixture
Control Screw 1-3
degrees clockwise.
Adjust pitch control
characteristics.
K
20