Doosan D20S-5 Operation & Maintenance Manual page 92

Operation Section Operation Section
Problem Problem
Engine Stalls Engine Stalls
Rough Idle Rough Idle
Probable Cause Probable Cause
Fuel Fuel Lock-off Lock-off malfunction malfunction
Faulty vapor connection between Faulty vapor connection between
the the pressure pressure regulator/converter regulator/converter
and the mixer and the mixer
Pressure Pressure regulator regulator freezes freezes
Pressure Pressure regulator regulator malfunctio malfunction n
Vacuum leak Vacuum leak
Air/Fuel Air/Fuel Mixer Mixer malfunctio malfunction n
Engine Mechanical Engine Mechanical
Faulty vapor connection between Faulty vapor connection between
the the pressure pressure regulator/converter regulator/converter
and the mixer and the mixer
Pressure Pressure regulator regulator malfunctio malfunction n
Vacuum leak Vacuum leak
Air/Fuel Air/Fuel Mixer Mixer malfunctio malfunction n
-89- -89-
Corrective Action Corrective
Repair/replace Fuel Repair/replace
See Engine Service Manual See Engine Service Manual
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Check connection Check connection
Verify no holes in hose Verify no holes in hose
 
Clamps must be tight Clamps must be tight
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Look Look for for
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collapsed hose collapsed hose
Check level Check level in in cooling
Must be full, check coolant strength Must be full, check coolant strength
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-35F minimum -35F minimum
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Check coolant hoses Check coolant hoses
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Watch for kinks and/or pinched hose Watch for kinks and/or pinched hoses s
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Verify one pressure hose and one Verify one pressure hose and one
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return hose return hose
Test pressure Test pressure regulator
See Engine Service Manual See Engine Service Manual
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Check Check for for vacuum vacuum leaks
Between mixer and throttle body Between mixer and throttle body
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Between throttle body and intake Between throttle body and intake
 
manifold manifold
Between intake manifold and cylinder Between intake manifold and cylinder
 
head head
Check mixer Check mixer
See Engine Service Manual See Engine Service Manual
 
See Engine See Engine Manufacturers Manufacturers Service
Check connection Check connection
Verify no holes in hose Verify no holes in hose
 
Clamps must be tight Clamps must be tight
 
Look Look for for
 
collapsed hose collapsed hose
Test pressure Test pressure regulator
See Engine Service Manual See Engine Service Manual
 
Check for Check for vacuum vacuum leaks
Between mixer and throttle body Between mixer and throttle body
 
Between throttle body and intake Between throttle body and intake
 
manifold manifold
Between intake manifold and cylinder Between intake manifold and cylinder
 
head head
Check mixer Check mixer
See Engine Service Manual See Engine Service Manual
 
Action
Fuel Lock-off Lock-off
kinked, kinked, pinched pinched and/or and/or
cooling system system
regulator operation operation
leaks
Service Manual Manual
kinked, kinked, pinched pinched and/or and/or
regulator operation operation
leaks