Doosan D20S-5 Operation & Maintenance Manual page 98

Operation Section
Problem
Rough Idle
High Idle Speed
Poor High Speed
Performance
Probable Cause
Incorrect Idle speed control
Incorrect timing or spark control
Engine Mechanical
Incorrect Idle speed control
Throttle sticking
Foot pedal sticking or incorrect
pedal signal
Clogged fuel filter
Plugged fuel line
Air filter clogged
Faulty vapor connection between
the pressure regulator/converter
and the mixer
Pressure regulator malfunction
Air/Fuel Mixer malfunction
Restricted exhaust system
Incorrect ignition control
Incorrect air/fuel control
Incorrect throttle position
Corrective Action
See Advanced Diagnostics & See Engine
Service Manual
See Engine Service Manual
See Advanced Diagnostics & See Engine
Service Manual
Check pedal return spring travel for binding
See Advanced Diagnostics
Repair/replace as required
See Maintenance section, Fuel Filter
replacement
Remove obstruction from the fuel line
Close liquid fuel valve
Using caution, disconnect the fuel line
(some propane may escape)
Clear obstruction with compressed air
Re-connect fuel line
Slowly open liquid fuel valve & Leak
test
Check air filter
Clean/replace as required
Check connection
Verify no holes in hose
Clamps must be tight
Look
collapsed hose
Test pressure regulator operation
See Engine Service Manual
Check mixer
See Engine Service Manual
Check exhaust system
Measure exhaust back pressure
See Advanced Diagnostics & See Engine
Service Manual
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for kinked, pinched and/or