Generac 8.1 GN Generator Set

⚠ Make sure the engine is at 60 to 80 F (16 to 27 C).

⚠ Hold the rocker arm jam nut in place as the pivot ball stud is turned.

⚠ Start all four screws before tightening.

Tools: 10 mm Allen wrench (530 cc engine), 13 mm Allen wrench (410, 990 and 999 cc engines), feeler gauge, socket wrench

1. Ensure engine is cool before checking; if clearance is 0.002-0.004 in (0.05-0.1 mm), adjustment is not needed.
2. Remove spark plug wires and position wires away from plugs; remove spark plugs.
3. Ensure piston is at Top Dead Center of its compression stroke (both valves closed).
4. Remove the four screws attaching the valve cover.
5. Loosen the rocker jam nut; turn the pivot ball stud while checking clearance with a feeler gauge.
6. Hold the pivot ball stud in place with the Allen wrench and tighten the rocker arm jam nut to 174 in-lb (19.68 N-m).
7. Recheck valve clearance to make sure it did not change.
8. Install new valve cover gasket and re-attach the valve cover.
9. Torque fasteners to 6-9 ft/lb (8-12 Nm).
10. Install spark plugs. Torque to 15-18 ft/lb (20-25 Nm).
11. Re-attach the spark plug wire to the spark plug.
12. Repeat the process for the other cylinder, if necessary.

⚠ Do not dispose of the battery by incineration.

⚠ Remove the 7.5 Amp ATO fuse from the control panel.

⚠ Remove all jewelry.

Tools: insulated tools

1. With the generator shut down, lift the lid and remove the front panel.
2. Inspect the battery posts and cables for tightness and corrosion; tighten and clean as necessary.
3. Check the battery fluid level of unsealed batteries and fill with distilled water only if necessary.
4. Have the Dealer or qualified technician check state of charge and condition.

1. With the generator shut down, lift the lid and remove the front panel.
2. Remove cover clips and air cleaner cover (11-22 kW), or disengage wire clip and open access door (8 kW).
3. Pull out the old air filter and discard.
4. Thoroughly clean the air cleaner enclosure of dust or debris.
5. Install a new air cleaner.
6. Install cover and clips (11-22 kW) or close door and engage wire clip (8 kW).

⚠ Do not overfill.

1. Run engine 5 minutes by pressing MANUAL; then press OFF.
2. Lift lid, remove front panel, pull oil drain hose free of retaining clip and drain oil.
3. Replace cap on oil drain hose and secure with retaining clip.
4. Remove old oil filter by turning counterclockwise.
5. Apply a light coating of clean engine oil to the gasket of the new filter.
6. Screw new filter on by hand until gasket lightly contacts adapter, then tighten 3/4 to one full turn.
7. Refill engine with proper recommended oil.
8. Start engine, run for 1 minute, and check for leaks.
9. Shutdown engine and recheck oil level; add oil as needed. Do not overfill.
10. Re-insert dipstick and/or reattach fill cap.
11. Press the Control Panel AUTO button.
12. Dispose of used oil and filter at a proper collection center.

⚠ Never operate the engine with the oil level below the Add mark.

⚠ Hot oil may cause burns.

1. Turn OFF all associated loads at the residence panel and set generator Main Circuit Breaker to OFF.
2. Press Control Panel OFF button. Wait 5 minutes.
3. Remove dipstick and wipe it dry with a clean cloth.
4. Completely insert the dipstick and again remove it.
5. Observe oil level; it should be at the Full mark on the dipstick.
6. If necessary add oil until level reaches Full, then reinsert dipstick and fill cap.
7. Press the Control Panel AUTO button.
8. Turn Main Circuit Breaker ON, then turn ON needed loads.

⚠ Never store the battery on any concrete or earthen floor.

1. Start the engine and let it warm up.
2. Close the fuel shutoff valve and allow the unit to shut down.
3. Set the Main Circuit Breaker to its OFF (OPEN) position.
4. Turn off the utility power to the transfer switch.
5. Remove the 7.5 Amp ATO fuse from the Control Panel.
6. Disconnect the battery cables; remove negative cable first.
7. Remove battery charger AC input T1/Neutral cable (white sleeve) at controller.
8. While warm, drain the oil completely, then refill the crankcase with oil.
9. Attach a tag indicating the viscosity and classification of the new oil.
10. Remove the spark plug(s) and spray a fogging agent into the threaded openings; reinstall and tighten.
11. Remove the battery and store it in a cool, dry room on a wooden board.
12. Clean and wipe down the entire generator.

⚠ Damage may occur if the battery is connected incorrectly.

1. Verify that utility power is turned off.
2. Check the tag on the engine for oil viscosity and classification; drain and refill with proper oil if necessary.
3. Check the battery state; fill unsealed cells with distilled water and recharge to 100%. Replace if defective.
4. Clean and wipe down the entire generator.
5. Make sure the 7.5 Amp ATO fuse is removed from the Control Panel.
6. Reconnect the battery, observing polarity; install positive cable first.
7. Reconnect the battery charger AC input T1/Neutral cable (white sleeve) at controller.
8. Open the fuel shutoff valve.
9. Insert the 7.5 Amp ATO fuse into the Control Panel.
10. Start the unit by pressing the MANUAL button and allow to warm up.
11. Stop the unit by pressing the Control Panel OFF button.
12. Turn on the utility power to the transfer switch.
13. Set the Control Panel to AUTO.

⚠ Do not blast the plug(s) to clean.

Tools: wire feeler gauge, wire brush

1. With the generator shut down, lift the lid and remove the front panel.
2. Clean the area around the base of the spark plug(s).
3. Remove spark plug(s) and check condition; install new if worn or reuse is questionable.
4. Clean plug(s) by scraping or washing with a wire brush and commercial solvent. Do not blast.
5. Check the spark plug gap using a wire feeler gauge and adjust by bending the ground electrode.

1. Make sure the transfer switch main contacts are set to their UTILITY position.
2. Be sure normal UTILITY voltage is available to transfer switch terminal lugs N1 and N2.
3. Press the AUTO button on the Control Panel Interface.
4. Set the Main Circuit Breaker (Generator Disconnect) to its ON (Closed) position.

⚠ DO NOT attempt to activate the transfer switch manually until all power voltage supplies to the switch have been completely turned off.

Tools: manual transfer handle

1. Press the Control Panel OFF button.
2. Set the Main Circuit Breaker (Generator Disconnect) to its OFF (OPEN) position.
3. Turn off the utility power supply to the transfer switch.
4. Use the manual transfer handle to move the main contacts to their STANDBY positions.
5. To crank and start the engine, press the Control Panel MANUAL button.
6. Allow the engine to stabilize and warm up for a few minutes.
7. Set the Main Circuit Breaker (Generator Disconnect) to its ON (CLOSED) position.

⚠ Set to AUTO, the engine may crank and start at any time without warning.

1. Press Escape until the MAIN MENU displays; navigate with up/down arrows.
2. Press Enter on the desired menu.
3. Set the Day/Time for exercise start.
4. Set exercise frequency to WEEKLY, BIWEEKLY or MONTHLY.
5. If monthly, select the date of the month for exercise.
6. Press the Control Panel AUTO button.