Thermo King UT-1200, Manual

Page: 100 / 169

Engine Maintenance
100
Electric Fuel Pump
Operation
The electric fuel pump must be mounted next to
the fuel tank. This pump is designed to push rather
than pull fuel.
Make sure the harness plug black wire pin
completes a good ground with the battery. Check
the voltage at the red wire pin of the harness plug.
The pump will not operate at less than 9 Vdc. The
pump is self priming as long as it is not higher
than 30 in. (762 mm) from the fuel in the fuel
tank.
Maintenance
The fuel pump filter should be cleaned whenever
the oil is changed. The filter and gasket are
replaceable but the pump cannot be repaired. It
must be replaced if it is defective.
Disassembly
1. Unscrew and remove the fuel filter bowl.
2. Unscrew the fuel filter.
3. Wash the fuel filter in cleaning solvent and
blow out the dirt and cleaning solvent with
compressed air.
4. Clean the fuel filter bowl.
5. Check the fuel filter bowl gasket and replace if
necessary.
Assembly
1. Screw the fuel filter back into the pump
housing (finger tight).
2. Place the fuel filter bowl gasket in place and
hand tighten (or 100 in-lb [11.3 N•m]) the fuel
filter bowl.
If the pump does not operate, check for:
• A good ground on the black wire pin of the
pump harness
• More than 9 Vdc on the red wire pin of the
pump harness
• Clean and tighten the electrical connections
• The pump voltage and polarity must be the
same as the unit system.
If the pump operates but does not deliver
fuel, check for:
• Air leaks in the fuel lines or connections
• Kinks or other restrictions in the fuel lines
• A leaking or distorted fuel bowl gasket
• A clogged or dirty filter.
1. Fuel Inlet
2. Fuel Filter
3. Fuel Filter Bowl
4. Fuel Filter Bowl Gasket
Figure 168: Electric Fuel Pump
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AMA703
AMA703