Generac GP6500 Generator Set

⚠ Ensure all material is clear of the alternator before proceeding.

Tools: VOM

1. Remove cover from end of alternator assembly.
2. Remove two screws holding down the voltage regulator (AVR).
3. Leave AVR connected to stator and brushes.
4. Set VOM to measure AC voltage.
5. Connect VOM across a 240VAC socket.
6. Set START-STOP-RUN switch to START.
7. Turn adjustment screw clockwise to increase voltage, counterclockwise to lower.

Tools: feeler gauge, crow foot wrench

1. Adjust valve clearance with engine at room temperature
2. Position piston at TDC of compression stroke (both valves closed), or set intake/exhaust valve fully open method
3. Loosen rocker arm jam nut; turn pivot ball stud while checking clearance with a feeler gauge
4. When clearance is correct, hold pivot ball stud and tighten rocker arm jam nut to specified torque with a crow foot wrench
5. Recheck valve clearance to make sure it did not change
6. Install rocker arm cover with a new gasket

Tools: AC frequency meter

1. Loosen governor clamp bolt
2. Hold governor lever at wide open throttle position
3. Rotate governor shaft counterclockwise (389/208/196cc) or clockwise (410cc) as far as it will go
4. Tighten governor lever clamp bolt to 110 in-lbs (389/208/196cc) or 70 in-lbs (410cc)
5. Turn speed adjustment screw counterclockwise three full turns to avoid overspeed
6. Start engine and let warm up under no-load
7. Connect AC frequency meter; no-load frequency should be 62.0-62.5 hertz
8. Turn speed adjust screw until frequency/RPM is within limits
9. Apply removable Loctite (Loctite 241) to speed adjust screw threads

⚠ Use a new rocker arm cover gasket.

Tools: feeler gauge, allen wrench, crow's foot

1. Adjust valve clearance with engine at room temperature.
2. Position piston at TDC of compression stroke (both valves closed).
3. Loosen the rocker arm jam nut.
4. Turn pivot ball stud while checking clearance with a feeler gauge.
5. Hold stud with allen wrench and tighten jam nut to specified torque with a crow's foot.
6. Recheck valve clearance after tightening.

⚠ Do not apply excessive torque to the governor shaft.

Tools: frequency meter

1. Loosen the governor lever clamp bolt.
2. Hold governor lever at full INC RPM; rotate governor shaft counterclockwise fully.
3. Tighten governor lever clamp bolt to 110 inch-pounds.
4. Turn speed adjustment screw counterclockwise three full turns.
5. Start engine and let it warm up and stabilize at no-load.
6. Connect frequency meter; set no-load frequency 62.0-62.5 hertz.
7. Add a drop of Loctite 241 to the speed adjust screw threads.

Tools: frequency meter

1. Loosen the governor clamp bolt.
2. Hold governor lever at wide open throttle; rotate governor shaft clockwise fully.
3. Tighten governor lever clamp bolt to 70 inch-pounds (8 Nm).
4. Start generator; let it stabilize and warm up at no-load.
5. Connect frequency meter across generator AC output leads.
6. Turn the primary adjust screw to obtain a frequency of 62.5 Hz.

Tools: VOM, AC frequency meter

1. Disconnect or turn OFF all electrical loads connected to the generator.
2. Set a VOM to measure AC voltage.
3. Reset all circuit breakers to the ON position.
4. Start engine and let it stabilize and warm up.
5. Place meter test leads into an outlet.
6. Read AC voltage; connect frequency meter and read frequency.

Tools: voltmeter (resistance)

1. Set a voltmeter to measure resistance.
2. Remove all wires from the START-RUN-STOP Switch.
3. Check terminal 2 to 1: CONTINUITY in START, INFINITY in STOP.
4. Check terminal 2 to 3: CONTINUITY in STOP, INFINITY in START.
5. Reconnect all wires to the switch.

⚠ DO NOT rotate engine with electric starter with spark plugs removed.

Tools: clamp-on ammeter, tachometer P/N 042223, 12 volt battery, starter test bracket

1. Remove starter motor and assemble to test bracket; clamp in vise.
2. Connect a fully charged 12 volt battery and clamp-on ammeter.
3. Activate the starter (jump terminal on Starter Contactor).
4. Note reading on clamp-on ammeter and tachometer.
5. Take readings after ammeter and tachometer stabilize (2-4 seconds).

Tools: cylinder leak down tester, compression gauge

1. Remove the spark plug.
2. Gain access to the flywheel and remove the valve cover.
3. Rotate crankshaft until piston reaches TDC (both valves closed).
4. Lock the flywheel at top dead center.
5. Attach leak down tester adapter to spark plug hole.
6. Connect an air source of at least 90 psi.
7. Adjust regulated pressure to 80 psi.
8. Read right hand gauge; 20 percent leakage is normally acceptable.

⚠ Do NOT insert the drill bit into the LED holes; damage to the LEDs will occur

Tools: 3/64 inch drill bit

1. Do not install CO badging (decal) prior to performing this test
2. Run generator under normal operation with no CO module notifications for a minimum of 65 seconds
3. With generator running, insert blunt end of a 3/64 inch drill bit into test switch hole
4. Hold the drill bit against the mounting panel until notification LEDs appear and generator shuts off
5. Successful pin test shows both LEDs on solid (not blinking)

1. Attempt to pull start the engine and observe.
2. Check whether the cord pulls easily and smoothly.
3. Check whether the cord returns with no assistance.
4. Check whether the engine turns over as the cord is pulled.