Doosan G430 LP Service Manual page 75

Power Mixture Adjustment
The method of adjustment depends upon the test
equipment that is available. The power mixture can be
adjusted using a CO meter, vacuum gauge or
electrical system analyzer. The CO meter method is
the preferred method for reduced emissions. The
vacuum gauge method is the next most accurate
method if CO measuring equipment is not available.
The engine speed method is the easiest but least
accurate method.
Power Mixture Adjustment.
Engine Speed Method
1. Connect the Electrical System Analyzer to read
engine rpm.
2. Check to be sure the ignition timing is set correctly.
3. Run the engine until normal operating temperature
is reached.
4. Turn the power mixture knob midway between lean
(L) and rich (R).
5. Accelerate the engine to high idle rpm. Put a load
on engine by holding the tilt cylinder against relief.
6. Turn the power mixture knob toward lean (L) until
engine rpm drops.
7. Turn the power mixture knob toward rich (R) until
the rpm recover.
8. The correct mixture will be that setting just before
the engine rpm drops.
LP Engine G430 (3.0L)
CO Meter Method
The power mixture adjustment must be done with the
engine in a load condition. A CO meter or exhaust
analyzer testing equipment must be used to measure
the CO content in the exhaust fumes. To adjust the
power mixture, turn knob either toward the "L" (lean)
or "R" (rich) fuel flow mixture for a 1.0 to 1.5 percent
CO indication on the test equipment. Start the
adjustment with knob in the middle position.
NOTE: A lift truck, that does not operate with a heavy
load all the time, can operate efficiently with a leaner
power mixture setting (less than 1.0 to 1.5 percent
CO). This is because the truck will not be in operation
constantly in a load condition for a long period of time.
During heavy load and high speed conditions the lift
truck requires a richer power mixture setting (1.0 to 1.5
percent CO).
Vacuum Gauge Method
1. Connect the vacuum gauge to the intake manifold.
Start and run the engine until normal operating
temperature is reached.
2. Run the engine at high idle. Turn power mixture
knob to the middle position.
3. Put a load on the engine by operating the hydraulic
system.
4. Monitor the vacuum gauge reading. Turn power
mixture adjustment knob toward the "L" (lean)
position, until the vacuum starts to drop. The correct
mixture is the point at which the vacuum starts to
drop.
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