O.S. engine Max-37SZ-Hring Owner's Instruction Manual page 17

Symptom
Unstable idle
Cause
Unsuitable glowplug
Unsuitable fuel
Silencer is disconnected or is loose
Symptom
Not reaching expected peak r.p.m.
Cause
Insufficient warming up or running-in.
Silencer or manifold is not securely connected
or disconnected.
Fuel tubing from tank to is split or broken.
Symptom
Poor response
Cause
Deteriorated glowplug
Incorrect carburetor settings
Inaccurate linkage
Symptom
Poor r.p.m. drop
Cause
Too much throttle opening at idle.
Incorrect carburetor installation
Needle valve closed too far.
Corrective action
Use suggested glowplug in the instructions.
Do not use extremely high nitro or low oil fuel.
Install silencer securely.
Corrective action
Set the needle only after warming up.
Complete running-in.
Check the connections and secure them.
Replace the tubing.
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Corrective action
Replace glowplug.
Readjust low r.p.m. range with metering
needle and mixture control valve.
Recheck the throttle opening against
the pith angle.
Corrective action
Lower the throttle trim to adequate position
to lower idling r.p.m.
Install carburetor securely.
Open needle-valve slightly
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