SkyTrak 8042 Service Manual - Manual (Page 341)

Engine: Cummins 4BT3.9 and 4BTA3.9
7A.18 Model 8042, 10042, 10054 Legacy Rev. 10/03
7A.8 FUEL SYSTEM
The fuel system includes a fuel tank (1), fuel level sender
with gasket (2), instrument cluster gauge (not shown),
fuel strainer (3), fuel lift pump (4), fuel filter (5), fuel supply
hose (6) and fuel return line (7).
The threaded fuel filler (8) has a fuel cap (9) and permits
entry of diesel fuel into the tank.
The fuel level sender (2) and instrument cluster gauge
are described in Section 9.14.15, “Fuel Level Indicator
and Fuel Level Sender.”
A fuel supply hose (6) carries fuel from the tank (1) to the
fuel lift pump (4) and then under pressure to the fuel filter
(5). Filtered fuel is directed to the fuel injection pump and
to the individual fuel injectors. Surplus fuel at the fuel
injector pump is returned to the tank via the fuel return
line (7).
7A.8.1 Diesel Fuel
Fuel represents a major portion of vehicle operating costs
and therefore must be used efficiently. ALWAYS use a
premium brand of high-quality, clean diesel fuel. Low
cost, inferior fuel can lead to poor performance and
expensive engine repair.
Note: Use only diesel fuel designed for diesel engines.
Some heating fuels contain harmful chemicals that can
seriously affect engine efficiency and performance.
IMPORTANT: Due to the precise tolerances of diesel
injection systems, keep the fuel clean, and free of dirt
and water. Dirt and water in the fuel system can cause
severe damage to both the injection pump and the
injection nozzles. Use ASTM #2 diesel fuel with a
minimum Cetane rating of 40. #2 diesel fuel gives the
best economy and performance under most operating
conditions. Fuels with Cetane numbers higher than 40
may be needed in high altitudes or extremely low
ambient temperatures to help prevent misfiring and
excessive smoking.
Inform the owner/operator of the vehicle to use #2 diesel
fuel, unless ambient temperatures are below 32° F (0° C).
When temperatures are below 32° F (0° C), a blend of #1
diesel and #2 diesel fuels (known as “winterized”
#2 diesel) may be used.
Note: #1 diesel fuel may be used, however, fuel
economy will be reduced.
Use a low-sulfur content fuel with a cloud point (the
temperature at which wax crystals form in diesel fuel) at
least 10° below the lowest expected fuel temperature.
The viscosity of the fuel must be kept above 1.3
centistrokes to provide adequate fuel system lubrication.
Note: When using diesel fuel with a sulfur content below
1.3 percent, the filter change interval must be reduced by
75 hours. The use of fuel with a sulfur content above
1.3 percent is not recommended.
WARNING:
DO NOT mix gasoline or
alcohol with diesel fuel. The mixture can cause
an explosion.