Doosan D20S-5 Operation & Maintenance Manual page 105

Problem
Poor High Speed
Performance
(Gas)
Problem
Poor High Speed
Performance
(Gas)
Probable Cause
Isolate the gasoline system by
running the lift truck on LPG
Clogged fuel filter
Plugged fuel line
Air filter clogged
Faulty vapor connection between
the pressure regulator/converter
and the mixer
Pressure regulator malfunction
Probable Cause
Air/Fuel Mixer malfunction
Restricted exhaust system
Incorrect ignition control
Incorrect air/fuel control
Incorrect throttle position
Corrective Action
Verify LPG cylinder is full and valve is open.
If the problem does not exist in LPG mode
proceed with the corrective action steps
below.
If the problem also exists in LPG mode then
the root cause is most likely to be
something other than the fuel system
See Advanced Diagnostics & Dual Fuel
Engine Service Manual
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 Dual Fuel Engine Service Manual
Corrective Action
Check mixer
See Engine Service Manual
Check exhaust system
Measure exhaust back pressure
See Advanced
Service Manual
-103-
Operation Section
for kinked, pinched
Diagnostics &
and/or
Engine