Secondary Fuel Filter Replacement; Priming The Fuel System - PREVOST H3-41 Maintenance Manual

SECTION 03 : FUEL SYSTEM
2.2.2

Secondary Fuel Filter Replacement

1. Stop engine, close the fuel supply line shut-
off valve. Place an appropriate container
under the fuel filter housing.
2. Clean around sealing area on fuel filter and
housing.
3. Unscrew and remove the secondary fuel
filter from the fuel filter housing.
4. Apply a thin coating of clean engine oil to
the gasket of the secondary fuel filter. Screw
the fuel filter into position. Tighten the filter
¾ to 1 turn after the gasket makes contact
with the fuel filter housing.
CAUTION
Fuel in the old filter must absolutely not be
poured into the new filter. This kind of
contaminated fuel can damage the unit
injectors.
5. Prime the fuel system by pumping the hand
priming pump on the fuel filter housing until
resistance is felt indicating that the system is
full of fuel.
6. Start the engine
fuel-tightness check. Let the engine run for
about 5 minutes to remove air pockets from
the fuel system.

2.3 PRIMING THE FUEL SYSTEM

The fuel system will need to be bled if:
 The vehicle has run out of fuel.
 The engine has not been running for an
extended period of time.
 Service work has been done on the fuel
system, (tank, fuel lines, filters, valves, etc.)
for example cleaning or replacing fuel filter
cartridges.
 The engine is new or rebuilt.
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PA1615 Maintenance Manual All Series
and carry out a
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Section 03 revised September 2016
CAUTION
When priming the system, movement of the
primer pump should be as up and down as
possible. Avoid putting any side load on the
pump or causing a binding condition. Failure
to follow these instructions could prematurely
damage the primer pump.
NOTE
When the fuel system is empty, 200 or more
pump strokes may be needed to properly
prime system. There are no bleed nipples to
be opened to prime the fuel system.
1. Stop engine;
2. Unlock the hand pump by turning the handle
counterclockwise.
3. Prime the system by moving the primer pump
in an up and down pumping motion. Avoid
putting any side load on the pump or causing
a binding condition.
FIGURE 6: HAND PRIMING PUMP
4. Lock the hand primer pump by retracting it
into the housing and turning it clockwise.
5. Start the engine and run it at an increased
idle speed for approximately 5 minutes to
remove any remaining air in the system.
Check the fuel system for leaks.