Generac 480c Engine

Tools: 10mm allen wrench, feeler gauge, crow's foot torque wrench

1. Adjust valve clearance with engine at room temperature, piston at TDC of compression stroke.
2. Loosen rocker arm jam nut, use 10mm allen wrench to turn pivot ball stud while checking clearance with feeler gauge.
3. Set intake valve clearance 0.002-0.004 in and exhaust valve clearance 0.002-0.004 in.
4. Hold pivot ball stud with allen wrench and tighten rocker arm jam nut to 174 inch-pounds with a crow's foot.
5. Recheck valve clearance after tightening jam nut.
6. Install rocker arm cover with new gasket and retain with four screws.

Tools: Pliers

1. Loosen governor clamp bolt.
2. Push spring end of governor lever clockwise to wide open throttle position.
3. Hold governor lever at wide open throttle and rotate governor shaft fully clockwise with pliers.
4. Tighten governor clamp bolt to 70 inch-pounds (8 N-m) while holding shaft and lever.
5. Start engine, let stabilize and warm up at no-load.
6. Turn adjuster nut to obtain 62 Hertz frequency reading.
7. Reposition governor spring in lever slot if droop is excessive or for greater stability.
8. Recheck frequency and readjust adjuster nut to obtain 62 Hertz at no-load.
9. Check AC voltage reading; adjust voltage regulator if incorrect.

⚠ Adjustment must be done only when unit is running at correct governed no-load speed

1. Run unit at no-load with frequency set to 62.5 Hz.
2. Slowly turn voltage adjust pot on voltage regulator until 124 VAC is measured.
3. If voltage is not adjustable, proceed to troubleshooting Problem 2.

⚠ Insulation resistance testers are a source of high and dangerous electrical voltage

Tools: Hi-pot tester or megohmmeter

1. Disconnect and isolate all stator leads including sensing, excitation, battery charge and power leads.
2. Connect terminal ends of all stator leads together.
3. Connect tester leads across all stator leads and to frame ground on stator can, apply 1500 volts for no more than 1 second.
4. If breakdown indicated, clean and dry stator and re-test; replace stator if it fails second test.

⚠ Damage will result if the battery connections are made in reverse.

1. Connect the battery cable from the POSITIVE (POS or +) post to the lug on the starter contactor.
2. Check that the battery cable boot for the starter cable has been installed.
3. Connect the battery cable from the NEGATIVE (NEG or -) post to the frame ground connection.
4. Connect cables so the connectors are clean and tight.

⚠ DO NOT USE ANY FLAME TO TEST FOR LEAKS.

Tools: soap and water solution, separate 12 volt DC source

1. Do not place the generator into service until the gas system has been properly tested for leaks.
2. Provide a separate source of 12 volts DC to open the gaseous fuel solenoid valve.
3. Test all connections, hoses, valve regulators and fittings under gas or air pressure of not less than 90 psi (620 kPa).
4. Use soap and water or an equivalent solution to check for leaks.

⚠ You must not allow the unit to overheat during prolonged operation.

1. Apply electrical loads equal to about 75 to 100 percent of the unit's rated wattage/amperage capacity.
2. Let the unit run at least 30 minutes with load applied.
3. Check that the unit is not running excessively hot and that adequate cooling airflow is available.

⚠ DO NOT FILL ABOVE THE 'FULL' MARK.

Tools: suitable container for oil, clean lint-free cloth

1. Run the engine until thoroughly warmed up (at least five minutes), then shut OFF the engine.
2. With the engine still warm, remove the oil drain plug and drain oil into a suitable container.
3. After the oil has drained, replace the oil drain plug (if only changing oil, go to step 7).
4. Remove the old oil filter by turning it counterclockwise.
5. Apply a light coating of clean engine oil to the gasket of the new filter.
6. Screw the new filter on by hand until its gasket lightly contacts the oil filter adapter; tighten an additional 3/4 to one turn.
7. Remove the dipstick and fill crankcase with proper oil; capacity about 1.8 liters or 1.9 quarts with filter change.
8. Install and tighten the dipstick before operating the engine.
9. Start the engine and check for leaks.

1. Disconnect breather tube and remove four screws and breather; discard gasket.
2. Check that reed valve is not deformed and forms complete seal around vent hole.
3. Remove oil vapor collector and retainer; check collector for deterioration, replace if necessary.
4. Install oil vapor collector and retainer, pushed in until it bottoms.
5. Install breather with new gasket, torque screws to 5-8 ft-lbs.
6. Assemble breather tube to intake elbow.

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

⚠ DO NOT FILL ABOVE THE 'FULL' MARK.

Tools: clean lint-free cloth

1. Be sure the generator is as level as possible.
2. Remove the dipstick and wipe it dry with a clean, lint-free cloth.
3. Install and tighten the dipstick cap, then remove it again; oil should be at 'Full' mark.
4. If necessary, remove oil fill cap on rocker cover and slowly add oil to the 'Full' mark.
5. Install and tighten the oil fill cap and the dipstick before operating the engine.

⚠ Do not blast the spark plug to clean.

Tools: wire brush, commercial solvent, wire feeler gauge

1. Clean the area around the base of the spark plug to keep dirt and debris out of the engine.
2. Remove the spark plug and check its condition; replace if worn or if reuse is questionable.
3. Check the spark plug gap with a wire feeler gauge and adjust to 0.030 inch (0.76 mm) by carefully bending the ground electrode.

⚠ DO NOT TWIST the foam precleaner

Tools: clean cloth

1. Turn the knob counterclockwise to loosen.
2. Remove the cover, foam precleaner and paper filter.
3. Remove the foam precleaner from the cover.
4. Wash the foam precleaner in liquid detergent and water.
5. Wrap the foam precleaner in a clean cloth and gently squeeze it dry.
6. Saturate the precleaner in clean engine oil, then squeeze out excess oil (DO NOT TWIST).
7. Install the precleaner into the cover, followed by the paper filter with tabs locked into cover slots.
8. Install the cover, foam precleaner and paper filter.
9. Replace knob to retain the filter in place.