Kohler COMMAND CV17-745 Service Manual page 74

Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
Section 5B
EFI Fuel System
General
The fuel pressure regulator assembly maintains the
required operating system pressure of 39 psi ± 3. A
rubber-fiber diaphragm (see Figure 5B-26) divides the
regulator into two separate sections; the fuel chamber
and the pressure regulating chamber. The pressure
regulating spring presses against the valve holder (part
of the diaphragm), pressing the valve against the valve
seat. The combination of atmospheric pressure and
regulating spring tension equals the desired operating
pressure. Any time the fuel pressure against the
bottom of the diaphragm exceeds the desired (top)
pressure, the valve opens, relieving the excess
pressure, returning the excess fuel back to the tank.
Pressure
Regulating
Spring
Valve
Inlet Port
Return Port (to tank)
Figure 5B-26. Fuel Pressure Regulator Details.
Service
Depending on the application, the regulator may be
located in the fuel tank along with the fuel pump, or
outside the tank just down line from the pump. The
regulator is a sealed, non-serviceable assembly. If it is
faulty, it must be separated from the base/holder
assembly and replaced as follows.
1. Shut engine off, make sure engine is cool, and
disconnect the negative (-) battery cable.
2. Depressurize fuel system through test valve in
fuel rail (see fuel warning on page 5B.2).
3. Access the regulator assembly as required and
clean any dirt or foreign material away from the
area.
4. External Regulator -
Based upon the style of regulator used: See Figure
5B-27.
5B.20
Pressure
Regulating
Chamber
Diaphragm
Valve Seat
Fuel Chamber
Outlet Port
(to fuel rail)
Figure 5B-27. External Regulators and Base/
Holders.
Figure 5B-28. Internal (In-Tank) Regulator and
Base/Holder.
5. Always use new O-Rings and Oetiker hose clamps
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a. Remove the two screws securing the
mounting bracket to the regulator housing.
Remove the O-Ring and pull the regulator out
of the housing.
b. Remove the snap ring and remove regulator
from base/holder.
Internal (In-Tank) Regulator -
Remove the three screws securing the retaining
ring and regulator in the base/holder assembly.
Grasp and pull the regulator out of the base/holder.
See Figure 5B-28.
when installing a regulator. A new replacement
regulator will have new O-Rings already installed.
Lubricate the O-Rings (external regulator) with light
grease or oil.