Engine System
26
Service Manual – PBU Propane Floor Burnisher
Fuel Regulator/Fuel Mixture
This adjustment sets the fuel flow for high and low idle, which determines the fuel to air mixture entering
the engine This procedure requires the removal of the anti-tampering caps from the pressure regulator
Make sure you have a new set of caps available before beginning the procedure
The procedure below uses the oxygen sensor for evaluating the engine performance An exhaust gas analyzer
may be used instead Use the parameters below if the exhaust gas analyzer is used
Target CO = 0 007%
Max CO = 0 02%
Max HC = 50 ppm
NOx = Less than 60 ppm
Equipment and Machine Setup
The following steps are required to setup the machine and
equipment for the testing/adjusting It will be easier to
complete these before the engine has warmed up However,
you may want to wait until you know that adjustments are
required before removing the anti-tampering caps on the
fuel regulator
1
Make sure the engine air filter is clean.
2 If the machine is not equipped with the CarbGard
engine monitoring system (oxygen sensor), remove the
plug from the exhaust manifold bung and temporarily
install an oxygen sensor
3 If the machine is equipped with the CarbGard engine
monitoring system, unplug the oxygen sensor connector
and install the voltmeter tap in-line with the original
connection
4 Connect a voltmeter between Ground (Battery
Negative) and the oxygen sensor tap
• Set the voltmeter to DC volts and the lowest
range that is appropriate to read a 0 to 1
volt signal
5 Remove the anti-tampering caps from the fuel
pressure regulator (You may want to wait
to complete this step until you know that an
adjustment is required )
a Carefully drill a small hole through the center of the
cap Take care not to allow the drill bit to damage
the adjustment screw under the cap
b Thread a small sheetmetal or wood screw into the
hole, and pull the cap off with a pliers
6 Start the engine and bring it up to operating
temperature at high idle
7 Verify that the engine low idle and high idle speeds
are within normal range as described on page 25
These speeds will be affected by this procedure, but they
should be close to begin with
Oxygen
Sensor
Exhaust
Manifold Bung
O
2
Sensor
Tap
Voltmeter
Probe
High Idle
Cover
Low Idle
Cover
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