Doosan D35C-5 FDA04 Operation & Maintenance Manual page 107

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
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 for kinked, pinched and/or

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
-105-
Operation Section
Corrective Action