O.S. engine PEGASUS 320 Owner's Instruction Manual page 11

Start the engine.
open the throttle fully .
Adjust the needle-valve.
Close the throttle gradually.
Set the idle speed.
Re-set the idle speed
a little higher
Open the throttle fully.
Does the engine
regain full power?
Engine stops.
Continue running at high speed
for 5 seconds.
Close the throttle.
Run at idle speed for 5 seconds.
Does the engine stop?
Engine stops.
Apply full throttle.
Does the engine
regain full power
immediately?
OK
Attention: Do not leave the battery connected while adjusting the carburetor.
Disconnect the glowplugs from the battery.
Approx 40˚ open from maximum
r.p.m. setting.
Make sure that all 4 cylinders are firing.
The position where the lowest
possible r.p.m. ,with steady
running, is obtained.
Set the throttle opening by
means of the throttle trim on
the transmitter so that the lowest
practical speed, without risk of
the engine stopping,is obtained.
Make sure glowplug switch is on.
The engine hesitates before picking
up to full speed, or appears to run at
medium speed with reduced power.
Yes.
Check mixture adjustment at idle
speed. Make sure that all cylinders
are firing.
Adjustment should be carried
out after stopping the engine.
Do not move needle-valve
while adjusting other controls.
No.
Yes.