Generac Power Systems GTH760, Service Manual

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NOTE: TEST REGULATOR ON ENGINE FIRST OR, FOR
SCHEDULED MAINTENANCE, PROCEED TO "REMOVE
REGULATOR AND DISMANTLE AS FOLLOWS".
1. Make sure the fuel tank(s) have an adequate supply
of fuel.
2. Make sure the valve on the tank is fully open (turned
counterclockwise).
Note: This fuel system is under high pressure.
3. While the fuel is off, install the primary pressure test gauge
at the 1/8” primary test port opening at the side of the
regulator, marked “PRI”. See Figure 3-14.
4. Disconnect the vapor hose at the Carburetor or Car-
buretor Adapter.
5. Turn on the ignition to open the fuel solenoid valve.
6. If the engine is equipped with an engine controlled safety
switch, bump the starter to make contact and open the
fuel solenoid valve.
7. Primary pressure should be 0.5 to 4.5 psi and hold
pressure.
8. If primary pressure is too high or too low and leakage
is observed at the vapor hose, the regulator must be re-
moved, disassembled, cleaned and new parts installed.
REMOVE REGULATOR AND DISASSEMBLE AS FOLLOWS:
*
Caution! Prior to the removal of any lP system com-
ponents, disconnect the battery and turn off the fuel
supply at the tank(s).
1. Remove the five secondary cover screws, 10-32 x 0.630”,
and lift the cover off the regulator body and secondary
diaphragm (see Figure 3-13). The cover has a tendency
to stick to the diaphragm and gasket. A slight tap on the
edge of the cover with a screwdriver handle or a soft face
hammer will loosen the cover.
Note: Do not pry in between the cover and the body.
Damage to the sealing surface may result.
2. After the cover has been removed, lift up an edge of the
diaphragm. Observe how it is attached to the secondary
lever. See Figure 3-14.
3. Remove the two screws, 10-32 x 0.310”, holding the
secondary lever pivot pin and remove the secondary
lever and spring. The secondary pivot pin is 1.20” long.
See Figure 3-15.
Figure 3-13. Remove Five Secondary Cover Screws
4. Remove the four screws, 10-32 x 0.630”, holding the
primary diaphragm cover in place. If the cover sticks, use
a screwdriver handle or soft-faced hammer to dislodge it.
Observe that the longer (2),10-32 x 1.0”, of the six screws
are at the top of the cover. Remove primary spring. See
Figure 3-16.
PRESSURE TEST POINT
Figure 3-14. Lift Edge of Diaphragm
5. Remove the primary diaphragm. See Figure 3-17.
6. Remove the two screws, 8-32 x 0.375” long. See
Figure 3-18.
Note: Remove oil and foreign deposits from all chambers
and parts. DO NOT APPLY LIQUID CLEANERS TO THE
DIAPHRAGMS AND NEOPRENE FACED VALVES.
3-6
SeCTIoN 3: CArbureTIoN ANd Fuel SYSTeM