Briggs & Stratton 040298, Service & Troubleshooting Manual

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Fuel Factors
An important consideration affecting the performance of the
generator is the type of fuel used. The system was factory
tested and adjusted using either natural gas or liquid propane
(LP). For proper engine function, important NG or LP factors
are:
• Use clean, dry fuel, free of moisture or any
particulate material. Using fuels outside the
following recommended values may cause
performance problems.
• In engines set up to run on propane (LP),
commercial grade HD5 propane with a minimum
fuel energy of 2500 BTUs/ft3 with maximum
propylene content of 5% and butane heavier gas
content of 2.5% and minimum propane content
of 90%.
Power Decrease at High Altitude or High Temperature
Air density is less at high altitudes, resulting in less available
engine power. Specifically, engine power will decrease 3.5%
for each 1,000 feet (300 meters) above sea level and 1% for
each 10° F (5.6°C) above 77°F (25°C). Generators located in
these conditions must have their transfer switch
programmed appropriately for this power decrease.
Fuel Consumption
The generator has been factory set to run on natural gas. If
you need to change from natural gas to LP gas, the unit will
need to be reconfigured, as described in
Reconfigure the Fuel
System .
The table below provides approximate fuel supply
requirements at half load and full load to ensure effective
generator operation.To check fuel supply pressure, use
#19495, Vacuum Tester.
• Natural gas fuel supply pressure at the generator
fuel inlet port should be between 5 to 7 inches of
water column (in. W.C.) at full load with all gas
appliances turned on and operating.
• LP gas fuel supply pressure should be 11 to 14
inches of water column (in. W.C.) at full load with
all gas appliances turned on and operating.
Reconfigure the Fuel System
The engine of your generator is factory calibrated to run on
natural gas (NG). It may also be operated on liquid propane
(LP). There is no additional hardware/equipment required to
switch between either fuel. However, LP fuel inlet pressure
must be between 11 and 14 inches water column at full load
with all gas appliances turned on and operating.
To reconfigure the fuel system for LP use:
1. Set control panel system switch to OFF .
2. Remove 15 Amp fuse.
3. Open oil fill access panel.
4. Remove four screws that secure roof to side panels
and lift off roof.
5. Remove screw at base of enclosure front panel ( A ,
Figure 6).
Figure 6
6. Remove two screws at front panel top corners from
inside enclosure.
7. Lift front panel off base ( B , Figure 7) and expose
muffler and engine ( C, Figure 8).
WARNING Propane and Natural Gas are extremely
flammable and explosive. Fire or explosion can
cause severe burns or death.
• The residential generator is equipped with an
automatic safety fuel shut-off valve.
• DO NOT operate the equipment if the fuel shut-off
valve is missing or inoperative.
Natural Gas LP Vapor
½ Load Full Load ½ Load Full Load
80 C 137 C 33 C 56 C
80,000 B 137,000 B 82,500 B 140,000 B
C = Cubic feet per hour
B = BTU’s per hour
Not
for
Reproduction