Generac Power Systems 53187 - Manual (Page 102)

PART 4
ENGINE FUEL SYSTEM SECTION 4.4
FUEL INJECTION PUMP
Section 4.4
FUEL INJECTION PUMP
Injection Pump Removal
Dits See Figure 1. Remove bolts and nuts that retain the
pump. Move the pump straight up and puil out the snap
pin. Remove the link from the pump control rack. Fi­
nally, remove the pump.
NOTE: Injection tim ing Is determ ined by SHIM S at
the Injection pum p m ounting face. Be sure to check
and record the thickness and num ber of shim s to
ensure proper Installation of the pum p.
Injection Pump Installation
Install the pump using the same shims that were
removed during disassembly. Connect control rack of
pump with link and retain with snap pin. Retain pump
with bolts and nuts.
Fuel Injection Timing
If the same pump is to be reinstalled, always use
the same number of shims that were removed. These
shims establish the fuel injection timing.
Timing will have to be readjusted whenever one or
more of the following components have been replaced:
□ When the injection pump is replaced.
□ When the camshaft has been replaced.
□ When the cylinder block has been replaced.
Figure 2. Delivery Holder, Spring, Delivery Valve
4. Move the governor control lever to its FULL IN­
CREASE position, to deliver fuel with No. 1 piston ar
around 25' BTDC of its compression stroke. Fuel will
flow from the delivery holder at this time.
5. Slowly turn the crankshaft clockwise (CW) until fuel
stops coming from the delivery holder. Check the piston
position at this point.
a. If the piston position is LATER than 16.5' BTDC,
use a thinner shim.
b. If the piston position is EARLIER than 17.5' BTDC,
use a thicker shim.
INJECTION TIMING PISTON POSITION
16.5'-17.5' BTDC 0.077-0.086 Inch BTDC
(1.95-2.19mm BTDC)
NOTE: W hen a shim Is NOT required, use liquid
packing to assem ble the Injection pum p.
To adjust fuel injection timing, proceed as follows: g Assemble the DELIVERY VALVE (IN).
1. Install the injection pump using a shim that is 0.5mm
(0.020 inch) thick.
2. Remove the DELIVERY HOLDER at the front of the
injection pump (Figure 2).
3. Remove the DELIVERY VALVE (IN). Reinstall the
SPRING and the DELIVERY HOLDER.
NOTE: W hen reassem bling the delivery holder, ad­
just the location of the delivery valve (OUT) with a
wire.
DELIVERY HOLDER TIGHTENING TORQUE
29-33 Ft.-Lbs. (4.0-4.5 m-kg)
NOTE: Injection tim ing shim s are available In the
following sizes: (a) 0.2m m (0.008 Inch), (b) 0.3m m
(0.012 Inch), (c) 0.5m m (0.020 Inch), (d) 1.0 m m
(0.040 Inch).
PAGE 4.4-1