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Generac GH-410 Engine

The Generac GH-410 is a 410 L 1-cylinder naturally aspirated engine rated at 3600 rpm. It powers generator sets from Generac, including the 8.1 GN. It holds 1.4 L (0.4 gal) of oil.

Also known as: GH-410, Generac GH-410

410.0 L

Displacement

Cylinders

3600 rpm

Rated speed

1.4 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Oil capacity	1.4 L
Displacement	410.0 L
Cylinders	1
Aspiration	Naturally aspirated
Rated speed	3600 rpm

Generator sets powered by this engine

Generac 8.1 GN

How to read your Generac engine serial & model number →

Common problems

The engine will not crank.
Cause: 1. Fuse blown.
Fix: Correct short circuit condition, replace 7.5A fuse in generator control panel.
The engine starts hard and runs rough.
Fix: 1. Out of fuel. 2. Defective fuel solenoid (FS). Open #14 wire from engine control board. 3. Fouled spark plug(s). 4. Valve lash out of adjustment. 5. Choke not operating.
The engine cranks but will not start.
Fix: 1. Loose, corroded or defective battery cables. 2. Tighten, clean or replace as necessary. 3. Defective starter contactor. (8 kW) 4. Defective starter motor. 5. Dead Battery.
The AUTO/OFF/MANUAL switch is set to OFF, but the engine continues to run.
Fix: 1. Replenish fuel/Turn on fuel valve. 2. Clean, re-gap or replace plug(s). 3. Confirm fuel pressure to regulator is 10-12” water column (0.36-0.43 psi) for LP, and 5-7” water column (0.18-0.25 psi) for natural gas. 4. Fuel selector in wrong position. 5. Choke remains closed.
Voltage and Frequency Drop Excessively When Loads Are Applied
Fix: TEST 14 - CHECK VOLTAGE AND FREQUENCY UNDER LOAD, BOTH LOW -> TEST 15 - CHECK FOR OVERLOAD CONDITION, NOT OVERLOADED -> GOOD -> IF RECONFIGURED TO LP GAS, VERIFY THAT PROPER PROCEDURE WAS FOLLOWED (REFER TO INSTALLATION MANUAL), GOOD -> OVERLOADED -> DISCONTINUE TESTING, REDUCE LOADS TO UNIT’S RATED CAPACITY, TEST 12 - CHECK STEPPER MOTOR CONTROL, GOOD -> BAD -> REPAIR OR REPLACE, LOOK FOR A SHORTED CONDITION IN A CONNECTED LOAD OR IN ONE OF THE LOAD CIRCUITS, GOOD -> TEST 7 - CHECK STATOR AC POWER WINDINGS, ENGINE CONDITION GOOD -> REPAIR OR REPLACE, BAD -> TEST 16 - CHECK ENGINE CONDITION, GOOD -> GO TO “PROBLEM 18 - ENGINE STARTS HARD AND RUNS ROUGH/LACKS POWER” SECTION 4.3
Unit consumes large amounts of oil.
Fix: 1. Engine over filled with oil. 2. See 'Engine Oil Recommendations'. 3. Check for oil leaks. 4. Engine breather defective.
There is no transfer to standby after utility source failure.
Fix: 1. Defective transfer switch coil. 2. Defective transfer relay. 3. Transfer relay circuit open. 4. Defective control logic board.
There is no AC output from the generator.
Fix: 1. Main line circuit breaker is in the OFF (or OPEN) position. 2. Generator internal failure.
Generator Produces Low Voltage at No-Load
Cause: Frequency is Low AND ADJUST FREQUENCY; Regulator is Defective
Fix: ADJUST FREQUENCY; REPLACE STATOR ASSEMBLY; REPLACE ROTOR ASSEMBLY; REPLACE VOLTAGE REGULATOR
Generator Produces High Voltage at No-Load
Cause: Frequency is Low AND ADJUST FREQUENCY; Regulator is Defective
Fix: ADJUST FREQUENCY; REPLACE VOLTAGE REGULATOR
Wiring Error ALARM 2099
Utility voltage is detected at DC terminal block
Cause: AC utility power sense wires mistakenly connected to DC terminal block
Fix: Remove power from controller, clear warning message
Utility failure 0
Fix: Crank and start engine, transfer load to Generator if Utility returns above 75% nominal for 15 seconds
Unstable Voltage or Incorrect Output Which is Not Triggering a Shutdown
Fix: TEST 1 - CHECK AC OUTPUT VOLTAGE, ERRATIC -> PROCEED TO PROBLEM 3
Unit consumes large amounts of oil 807
Fix: Adjust oil to proper level. See 'Engine Oil Recommendations'. Check for oil leaks.

Compiled from service & troubleshooting documentation across every generator set that uses the Generac GH-410.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter			0C8127	200 hr	Amazon eBay $15.99 NAPA $24.03 FridayParts $21.87
Fuel filter	Fuel Requirements and Recommendations		—
Oil filter			070185		Amazon eBay $30.00 NAPA $3.59 FridayParts $45.99
Battery	Group 26R, 12 Volts and 350 CCA minimum (8kW); Group 26R, 12 Volts and 525 CCA minimum (10/13/14/16/17/20kW)		0H3421S	1000 hr	Amazon eBay $283.32
Belt			0A5275		buy
Coolant	Cooling System	2.0 U.S. gallons	—	250 hr
Oil	Checking the Engine Oil Level	1.9 Qts	—	250 hr
Spark plug	0.030 inch for single cylinder engines and 0.020 inch for v-twin engines		072347		eBay $1.99

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Repair guides

Step-by-step procedures compiled from the Generac service manual for this engine.

Service intervals

Item	Action	Hours	Months	Notes
Oil	Change	200 hr	24 mo	First service — Change oil after first eight (8) hours of operation
Oil filter	Change	200 hr	24 mo	First service — Change oil filter after first eight (8) hours of operation
Oil and filter	Change	25 hr		First service — After first 25 hours of operation
Engine governor oil level	Check	50 hr		Check prior to initial use and every 50 operating hours thereafter.
Exercise	Test	168 hr		Weekly exercise
Oil filter	Replace	200 hr	24 mo	200 hours or 2 years, whichever occurs first
Service Schedule A	Other	200 hr	24 mo	200 hours or 2 years
Air cleaner	Clean	400 hr		Clean or replace as necessary; R = Replace as Necessary; 400 hours
Air cleaner	Inspect	400 hr	24 mo	Inspect and change; every 400 hours
Service Schedule B	Other	400 hr	48 mo	400 hours or 4 years
Spark plug(s)	Clean	400 hr		Replace every 4 years or 400 hours
Spark plug(s)	Inspect	400 hr	24 mo	Inspect and change; every 400 hours (recommended every 4 years or 400 hours)
Valve clearance	Adjust	500 hr		First service — Check after first 25 hours; continue at 400-hour intervals
Air cleaner	Replace	200 hr	24 mo	Yearly (inspect and replace as necessary)
Battery	Check		12 mo	Check charge state; yearly
Battery	Clean		12 mo	Remove corrosion, ensure dryness; yearly
Battery (remove corrosion, ensure dryness)	Inspect		12 mo	Yearly
Battery - check charge state	Test		6 mo	Every 6 months; replace as necessary
Battery - electrolyte level (unsealed batteries only)	Check		6 mo	Every 6 months; replace as necessary; notify dealer if repair needed
Battery - remove corrosion, ensure dryness	Clean		1 mo	Monthly (inspect and clean)
Battery charge state	Check		12 mo	Yearly
Battery charge state	Test		6 mo	Every 6 months; replace as necessary
Battery electrolyte level	Check		6 mo	Unsealed batteries only; every 6 months; notify Dealer if repair is needed
Battery electrolyte level (unsealed batteries only)	Check		6 mo	Every 6 months
Battery terminals	Clean		12 mo	Monthly; clean and tighten
Battery terminals (clean and tighten)	Clean		12 mo	Yearly
Complete tune-up	Other	200 hr	24 mo	Yearly; to be completed by a Generac/Guardian Authorized Dealer
Electrolyte level	Check		6 mo	Every 6 months
Fuel lines and connections	Inspect		1 mo	Notify dealer if repair is needed; Monthly
General condition (vibration, noise, leakage)	Inspect		1 mo	Notify dealer if repair is needed
Oil level	Check	24 hr	1 mo	Monthly or 24 hours of continuous operation
Spark plug(s)	Replace	400 hr	24 mo	Yearly (inspect and replace as necessary)
Valve clearance	Check	400 hr	6 mo	First service — After the first six (6) months of operation; adjust if necessary
Vibration, Noise, Leakage	Inspect		1 mo	Notify dealer if repair needed; Monthly
Vibration, Noise, Leakage, Temperature	Inspect		1 mo	Monthly; notify dealer if repair is needed

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Valve clearance	0.002 - 0.004 inch (0.05 - 0.1 mm)	inch (mm)	engine cool
Gap	Armature Air Gap	0.008-0.012	inch
Gap	Breaker Point Gap	0.018-0.022	inch
Gap	Ignition magneto (armature) air gap	0.008-0.012 inch (0.20-0.30mm)	inch	V-twin engines; not adjustable on single cylinder engines
Gap	Ignition magneto air gap	0.008-0.012 inch (0.20-0.30 mm)	gap	V-twin engines; fixed non-adjustable on single cylinder
Gap	Spark Plug Gap	0.031-0.035	inch
Gap	Spark plug gap	0.020	inch (0.508 mm)
Gap	Spark plug gap	0.030	inch	8, 10 & 20kW
Gap	Spark plug gap	0.040	inch	12, 14, 16 & 17kW
Gap	Spark plug gap	0.508	mm
Gap	Spark plug gap	0.76	mm (0.030 inch)
Gap	Spark plug gap	0.76 mm (0.030 inch)	gap	410 cc and 530 cc engines
Gap	Spark plug gap	1.02	mm (0.040 inch)
Gap	Spark plug gap	1.02 mm (0.040 inch)	gap	990 cc and 999 cc engines
Gap	Spark plug gap (12/15 kW)	0.508	mm (0.020 inch)
Gap	Spark plug gap (410 cc, 7 kW)	0.030	inch
Gap	Spark plug gap (530 cc, 10 kW)	0.030	inch
Gap	Spark plug gap (7 kW)	0.76	mm (0.030 inch)
Gap	Spark plug gap (990 cc, 13-16 kW)	0.040	inch
Other	Compression Ratio GH-410	8.6:1
Other	Compression Ratio GT-530	9.5:1
Other	Compression Ratio GT-990	9.5:1
Other	Compression Ratio GT-999	9.5:1
Other	Compression ratio	8.6:1
Other	Compression ratio	9.5:1
Other	DC amperage (full wave AVR, 15-20 kW)	0.6-0.75	amps
Other	DC amperage (half wave AVR, 7-10 kW)	1.0-1.5	amps
Other	Minimum allowable compression pressure, cold engine (single cylinder)	60	psi	cold
Other	Rated Horsepower @ 3,600 rpm GH-410	14.8	HP
Other	Rated Horsepower @ 3,600 rpm GT-530	18	HP
Other	Rated Horsepower @ 3,600 rpm GT-990	32	HP
Other	Rated Horsepower @ 3,600 rpm GT-999	36	HP
Other	Starter motor performance - maximum amps	62	Amps	V-twin
Other	Starter motor performance - maximum amps	9	Amps	single cylinder
Other	Starter motor performance - minimum rpm	3250	rpm	V-twin
Other	Starter motor performance - minimum rpm	4500	rpm	single cylinder
Other	Starter motor performance, V-twin	Minimum rpm 3250; Maximum Amps 62
Other	Starter motor performance, single cylinder	Minimum rpm 4500; Maximum Amps 9
Pressure	Compression Difference Between Cylinders	14	psi
Pressure	Compression pressure	150	psi	cold engine
Pressure	Compression pressure	160	psi	cold engine
Pressure	Compression pressure	165	psi	cold engine
Pressure	Compression pressure	190	psi	cold engine
Pressure	Crankcase vacuum	-5 to -10	inches w.c.	engine running
Pressure	Cylinder leak down test regulated pressure	80	psi	air source of at least 90 psi
Pressure	Cylinder leak down tester regulated pressure	80	psi	air source at least 90 psi
Pressure	Engine Compression Minimum	164	psi	at 350 rpm
Pressure	Engine Compression Standard	192	psi	at 350 rpm
Pressure	Engine oil pressure	10-50	PSI (0.7-3.5 Bar)	engine running
Pressure	Fuel pressure LP	10 to 12	inches water column	required
Pressure	Fuel pressure at fuel solenoid inlet - LP gas	10 to 12	inches water column	LP
Pressure	Fuel pressure at fuel solenoid inlet - natural gas	5 to 7	inches water column	NG
Pressure	Fuel pressure drop between static and dynamic	0.5	inches w.c.	maximum
Pressure	Fuel pressure natural gas	5 to 7	inches water column	required
Pressure	Fuel pressure to regulator (LP)	10-12	inches water column (19-22 mm mercury)
Pressure	Fuel pressure to regulator (NG and LP)	11-14	inches of water column (0.6 psi)	at all load ranges
Pressure	Fuel pressure to regulator (natural gas)	3.5-7	inches water column (7-13 mm mercury)
Pressure	Fuel pressure to regulator - LP	10-12	inches water column (19-22 mm mercury)
Pressure	Fuel pressure to regulator - natural gas	3.5-7	inches water column (7-13 mm mercury)
Pressure	Fuel pressure under load	11"-14" water column	inches water column	generator running and under load

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50 percent soft water and 50 percent ethylene glycol base anti-freeze	low silicate anti-freeze		2.0 U.S. gallons	Do not use chromate base rust inhibitor or high silicate anti-freeze boosters.
Engine oil	10W-30	API Service Class SJ, SL or better			For expected operating temperatures between 40 °F and -10 °F
Engine oil	30 weight organic oil (factory fill)				Units run and tested at factory prior to shipping, no break-in required
Engine oil	5W-30	API SJ/CF			Use only API SJ/CF 5W-30 synthetic oil. Select the best viscosity for the outdoor temperature range expected. DO NOT use special additives.
Engine oil	SAE 30	API Service Class SJ, SL or better			For expected operating temperatures above 32 °F
Engine oil	SAE 30 above 32°F; 10W-30 between 40°F and -10°F; Synthetic 5W-30 10°F and below	API Service Class SJ, SL or better; use no special additives		1.5 Qts	Oil capacity including filter
Engine oil	SAE 40 above 86 F; SAE 30 32-85 F; SAE 20W below 32 F; SAE 10W-30 all seasons	API Service SC, SD, SE or SF		3.0 U.S. quarts	Liquid-cooled 1.2 liter engine with filter change; 2.5 U.S. quarts without filter change.
Engine oil	SAE 5W-20/5W-30	API Service class SG, SH, or SJ	below -7°C		Below 20° F (-7° C)
Engine oil	SAE 5W-30 Synthetic	API Service class SG, SH, or SJ			For all seasons
Engine oil	SAE 5W-30 Synthetic (all season)	API Service Class SG, SH or SJ		1.5 Qts	Organic break-in oil required before using synthetic oil; unit is supplied with break-in oil
Engine oil	SAE 5W-30 synthetic; SAE 30 above 60 F; SAE 10W-30 20-59 F; SAE 5W-20/5W-30 below 20 F	API Service SF, SF/CC, or SF/CD		1.5 U.S. quarts	Air-cooled V-Twin engine crankcase capacity about 1.5 U.S. quarts. Oil makeup tank capacity about 2.5 U.S. quarts on Model 9067.
Engine oil	Synthetic 5W-30	API Service Class SJ, SL or better			For expected operating temperatures 10 °F and below
Engine oil	SAE 10W-30	API Service class SG, SH, or SJ	-7°C to 15°C		20° to 59° F (-7° to 15° C)
Fuel		Natural gas at least 1,000 Btus per cubic foot; LP gas at least 2,520 Btus per cubic foot			Required fuel pressure: natural gas 5 to 7 inches water column (0.18 to 0.25 psi); liquid propane 10 to 12 inches water column (0.36 to 0.43 psi)
Fuel	Liquid Propane (LP) Vapor	Btu content at least 2,520 Btus per cubic foot; pressure 10-12 inches water column (0.36-0.43 psi)			Use vapor withdrawal system only
Fuel	Liquid propane (LP) gas (vapor)	at least 2,500 Btus per cubic foot (93.15 megajoules per cubic meter)		250.0 gallons (946 liters)	Minimum LP tank size recommended when converting from natural gas
Fuel	Liquid propane (LP) vapor	Btu content at least 2,520 Btus per cubic foot			Use only vapor withdrawal system; fuel pressure 10-12 inches water column required
Fuel	Natural Gas	Btu content at least 1,000 Btus per cubic foot; pressure 5-7 inches water column (0.18-0.25 psi)
Fuel	Natural Gas or LP (propane) vapor withdrawal				Natural gas at least 1000 BTU per cubic foot; LP at least 2520 BTU per cubic foot. Fuel pressure 11-14 inches water column.
Fuel	Natural Gas or LP Vapor				Fuel pressure: NG 3.5-7 in WC (Evolution), 5-7 in WC (Nexus); LP 10-12 in WC
Fuel	Natural gas	Btu content at least 1,000 Btus per cubic foot			Fuel pressure 5-7 inches water column required
Fuel	Natural gas (pipeline)	at least 1,000 Btus per cubic foot (37.26 megajoules per cubic meter)			Unit is factory set to run on natural gas
Fuel	Natural gas minimum 1,000 Btus per cubic foot; LP vapor minimum 2,520 Btus per cubic foot	1997 California Air Resources Board (tamper-proof dual fuel system)			Supply pressure must be 11-14 inches water column (0.6 psi); factory set for natural gas
Fuel	Natural gas or LP gas (vapor withdrawal only for LP)	Natural gas Btu content at least 1,000 Btus per cubic foot; LP gas at least 2,520 Btus per cubic foot			Required fuel pressure: NG 5 to 7 inches water column; LP 10 to 12 inches water column. NFPA 54 for natural gas, NFPA 58 for liquid propane.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Fault codes

Code	Name	Meaning	Severity	Action
1100	Overcrank	Engine Cranks but will not Start (5 crank attempts)	Shutdown	Problem 17
1200	Overspeed	Prolonged over specified Hz for 3 seconds	Shutdown	Test 12
1205	Overspeed	Instantaneous over specified Hz for 0.1 second	Shutdown	Test 12
1207	Overspeed	Monitors zero cross timing of AVR; 150 ms of 4500 rpm or higher	Shutdown	Test 64 and Test 60
1300	Low Oil Pressure	Occurred while running; check oil level and pressure	Shutdown	Test 61
1400	High Temperature	Air flow impeded; check inlet/outlet for debris	Shutdown	Test 62
1501	RPM Sensor	Twin Cylinder+Running; RPM sensor loss	Shutdown	Test 50 and Test 64
1505	RPM Sensor	Twin Cylinder+Cranking; RPM sensor loss	Shutdown	If engine cranks, Test 64. If not crank, Problem 15.
1511	RPM Sensor	Single Cylinder+Running; RPM sensor loss	Shutdown	Test 50 and Test 64
1515	RPM Sensor	Single Cylinder+Cranking; RPM sensor loss	Shutdown	If engine cranks, Test 64. If not crank, Problem 15.
1600	Underspeed	Unit is overloaded, slowing engine speed, fuel supply low or throttle control problem	Shutdown	Problem 3, or Test 50, or Test 12
1800	Overvoltage	Prolonged over-voltage	Shutdown
1900	Undervoltage	Prolonged under-voltage; below 80% for 10+ seconds	Shutdown	Preliminary Output Voltage Test
1901	Undervoltage	Instantaneous under-voltage due to sudden loss of voltage	Shutdown	Preliminary Output Voltage Test
1902	Undervoltage	Both zero crosses missing; faulty excitation winding or zero cross circuit	Shutdown	Preliminary Output Voltage Test
1906	Undervoltage	Single zero cross missing; faulty excitation winding or zero cross circuit	Shutdown	Preliminary Output Voltage Test
2099	Wiring Error	Mis-wired; customer connection low voltage and high voltage wires crossed	Shutdown	Check customer connection in generator
2100	Overload Remove Load	Overloaded - Default; one or both CTs detecting overload	Shutdown	Remove Load
2299	Undervoltage Overload	Unit was overloaded and attempted to start with large load	Shutdown	Remove Load
2399	Stepper Overcurrent	Current flow in stepper coil(s) above specification	Shutdown	Test 12
2400	Fuse Problem	Missing or damaged 7.5 amp controller fuse	Shutdown	Test 44
2800	Aux Shutdown	External shut down circuit is open	Shutdown	Check continuity of harness and operation of switch(es). Repair/replace as needed.
BATTERY PROBLEM	Battery Problem	Yellow LED illuminated	Warning	Contact servicing dealer.
CHARGER MISSING AC	Charger Missing AC	Battery charger missing AC input	Warning
CHARGER WARNING	Charger Warning	Yellow LED illuminated	Warning	Contact servicing dealer.
EXERCISE SET ERROR	Exercise Set Error	Exercise timer setting error	Warning
Exercise Set Error	Exercise Set Error	Warning; displayed if the exercise period becomes corrupted	Warning	Reset the exercise period to clear
FUEL PRESSURE	Fuel Pressure	Fuel pressure warning	Warning
FUSE PROBLEM	Fuse Problem	Unit will not start in AUTO with utility loss	Warning	Check ATO 7.5 amp fuse. Replace with same type fuse if bad. Contact servicing dealer if fuse is good.
HIGH TEMPERATURE	High Temperature	Unit shuts down during operation	Shutdown	Check ventilation around the intake, exhaust and rear of generator. Contact servicing dealer if no obstruction is found.
High Engine Temperature	High Engine Temperature	Shutdown alarm, auto reset; 10 second delay on start-up and 1 second delay before shutdown; contacts close if temperature exceeds approximately 144 °C (293 °F)	Shutdown	Auto reset when condition clears and restart engine if a valid start signal is present
INSPECT BATTERY	Inspect Battery	Battery inspection reminder	Info	Inspect battery; press ENTER to clear.
INTERNAL FAULT	Internal Fault	Internal controller fault	Shutdown	Contact servicing dealer.
Internal Fault	Internal Fault	Shutdown alarm; this alarm cannot be cleared	Shutdown	Call service dealer
LOW BATTERY	Low Battery	Yellow LED illuminated	Warning	Clear alarm; check battery via control panel BATTERY MENU; if GOOD contact dealer, else replace battery
LOW OIL PRESSURE	Low Oil Pressure	Unit will not start in AUTO with utility loss	Shutdown	Check oil level. Add oil per Owner's Manual. Contact servicing dealer if oil level is correct.
LOW VOLTS REMOVE LOAD	Low Volts Remove Load	Unit will not start in AUTO with utility loss	Shutdown	Clear alarm and remove household loads, put back in AUTO and restart
Low Battery	Low Battery	Warning; battery voltage below 11.9 volts for one (1) minute; clears automatically if voltage rises above 12.4 volts; not monitored during crank cycle	Warning	Service or charge battery
Low Oil Pressure	Low Oil Pressure	Shutdown alarm; 5 second delay on start-up and 7 second delay once running; switch contacts close if oil pressure drops below the five (5) PSI range	Shutdown	Verify oil level; unit should not be restarted until oil level is verified
MISWIRE	Miswire	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer
Maintenance Message	Maintenance Message	Maintenance alert; displayed when a maintenance period expires	Info	Press Enter to confirm reset; clears the alert and resets maintenance counters
NOT ACTIVATED	Not Activated	Unit will not start in AUTO with utility loss	Warning	Refer to activation section in owners manual
OVER VOLTAGE	Over Voltage	Overvoltage alarm	Shutdown	Contact servicing dealer.
OVERCRANK	Overcrank	Unit will not start in AUTO with utility loss	Shutdown	Check fuel line shutoff valve is in the ON position. Clear alarm. Attempt to start in MANUAL. If it does not start or starts and runs rough, contact servicing dealer.
OVERLOAD REMOVE LOAD	Overload Remove Load	Unit shuts down during operation	Shutdown	Clear alarm, remove household loads, put back in AUTO and restart
OVERLOAD WARNING	Overload Warning	Overload warning	Warning
OVERSPEED	Overspeed	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer.
OVERVOLTAGE	Overvoltage	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer
Over Crank	Over Crank	Shutdown alarm; occurs if the engine has not started within the specified crank cycle	Shutdown	Reset the control board and restart up to two more times if necessary
Over Speed	Over Speed	Shutdown alarm; 4320 RPM for three (3) seconds or 4500 RPM immediately	Shutdown	Contact the nearest Dealer if this failure occurs
Overvoltage	Overvoltage	Shutdown alarm; above 110% of rating for greater than three (3) seconds, or above 130% of rating for greater than 0.2 seconds	Shutdown	Check generator output
RPM SENSE LOSS	RPM Sense Loss	Unit was running and shuts down, attempts to restart	Shutdown	Clear alarm, remove household loads, put back in AUTO and restart; may be fuel issue, contact servicing dealer
RPM Sense Loss	RPM Sense Loss	Shutdown alarm; if no valid RPM signal within three (3) seconds during cranking, or lost for one (1) second while running	Shutdown	Control board shuts down, waits 15 seconds, then re-cranks; may re-crank once more before latching out
SERVICE A	Service Schedule A	Yellow LED illuminated, maintenance due	Info	Perform SERVICE A maintenance; press ENTER to clear.
SERVICE B	Service Schedule B	Yellow LED illuminated, maintenance due	Info	Perform SERVICE B maintenance; press ENTER to clear.
STEPPER OVER CURRENT	Stepper Over Current	Stepper motor over current	Shutdown	Contact servicing dealer.
STEPPER OVERCURRENT	Stepper Overcurrent	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer
UNDER VOLTAGE	Under Voltage	Undervoltage alarm	Shutdown	Contact servicing dealer.
UNDERSPEED	Underspeed	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer.
UNDERVOLTAGE	Undervoltage	Unit will not start in AUTO with utility loss	Shutdown	Contact servicing dealer
Under-frequency	Under-frequency	Shutdown alarm; if generator stays under frequency for more than 30 seconds; setting is 50 Hz	Shutdown	Check generator output
Undervoltage	Undervoltage	Shutdown alarm; if generator voltage falls below 60% of nominal for more than five (5) seconds	Shutdown	Check generator output and loads
WARNING	Low Battery	Battery less than 12.1 Volts for 60 seconds	Warning	Test 45
WIRING ERROR	Wiring Error / Miswire	Controller wiring error	Shutdown	Contact servicing dealer.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Adjust Magneto Flywheel Gap adjustment

Tools: 0.008-0.012 inch thickness gauge, screwdriver

Rotate flywheel until magnet under module.
Insert 0.008-0.012 inch non-metallic thickness gauge.
Loosen mounting screws.
Let magnet pull magneto against gauge.
Tighten screws.
Remove gauge by rotating flywheel.

Adjusting GH-410/GT-530/990/999 Valve Clearance adjustment

⚠ The engine should be cool before checking.

Tools: Feeler gauge, 10mm allen wrench, Socket wrench

Remove spark plug wires and position wires away from plugs.
Remove spark plugs.
Make sure the piston is at Top Dead Center (TDC) of its compression stroke.
Make sure the engine is at 60 to 80 F.
Remove the four screws attaching the valve cover.
Loosen the rocker jam nut.
Use a 10mm allen wrench to turn the pivot ball stud while checking clearance between the rocker arm and valve stem with a feeler gauge.
When valve clearance is correct, hold the pivot ball stud in place and tighten the rocker arm jam nut to 174 in/lbs torque.
Recheck valve clearance.
Install new valve cover gasket and re-attach the valve cover.
Install spark plugs and re-attach the spark plug wire.
On the GT-530 and GT-990/999, repeat the process for the other cylinder.

Adjusting GH-410/GT-990 Valve Clearance adjustment

⚠ Hold the rocker arm jam nut in place as you turn the pivot ball stud.

Tools: #2 or #3 Phillips screwdriver, 10mm allen wrench, feeler gauge, socket wrench

Make sure the engine is at room temperature.
Remove the spark plug wire from the spark plug.
Remove the four screws attaching the valve cover.
Set the piston at Top Dead Center of its compression stroke.
Loosen the rocker jam nut; turn the pivot ball stud; check clearance with a feeler gauge.
Tighten the rocker arm jam nut to 174 in/lbs.
Install a new valve cover gasket and re-attach the valve cover.
Re-attach the spark plug wire; on GT-990 repeat for the other cylinder.

Adjusting Magneto Flywheel Gap adjustment

⚠ Air gap between ignition magneto and flywheel on single cylinder engines is not adjustable.

Tools: 0.008-0.012 inch thickness gauge

Rotate the flywheel until the magnet is under the module (armature) laminations.
Place a 0.008-0.012 inch (0.20-0.30mm) thickness gauge between flywheel magnet and module laminations.
Loosen the mounting screws and let the magnet pull the magneto down against the thickness gauge.
Tighten both mounting screws.
To remove the thickness gauge, rotate the flywheel.
Repeat the above procedure for the second magneto.

Adjusting Valve Clearance adjustment

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

Tools: 10mm allen wrench, feeler gauge, socket wrench

Engine should be cool before checking.
Remove spark plug wires and position away from plugs.
Remove spark plugs.
Position piston at Top Dead Center (TDC) of compression stroke.
Remove four screws attaching valve cover.
Loosen rocker jam nut.
Turn pivot ball stud with 10mm allen wrench while checking clearance.
Tighten jam nut to 174 in/lbs torque and recheck clearance.

Adjusting Valve Clearance GH-410/GT-530/990/999 adjustment

⚠ Check valve clearance after first six (6) months of operation.

Tools: 10mm allen wrench, Feeler gauge, Socket and socket wrench

Engine should be cool before checking; clearance 0.002-0.004 inch needs no adjustment.
Remove spark plug wires and spark plugs.
Set piston at Top Dead Center of its compression stroke.
Remove four screws attaching the valve cover.
Loosen rocker jam nut; turn pivot ball stud with 10mm allen wrench.
Set clearance to 0.002-0.004 inch (0.05-0.1 mm).
Hold pivot ball stud and tighten jam nut to 174 in/lbs torque.
Install new valve cover gasket and re-attach valve cover.

Adjusting the Fuel Regulator - 7kW (Natural Gas Only) adjustment

⚠ Do not make any unnecessary adjustments. Factory settings are correct for most applications.

Tools: frequency meter

Start the generator; let it stabilize and warm up at no-load.
Connect a frequency meter across the generator's AC output leads.
Turn the primary adjust screw to obtain a frequency reading.

Adjusting the Regulator (Natural Gas Only) adjustment

⚠ Do not remove any of the set pins.

⚠ Be careful to avoid overspeeding the engine.

Tools: frequency meter

Turn off utility power to the main distribution panel.
Allow the generator to start; confirm no load frequency is 63-63.5 Hz.
Transfer load to emergency circuits and fully load the generator.
Connect a frequency meter to the output lugs of the main line circuit breaker.
Slowly turn the adjustment screws one at a time until the highest frequency is read.
Turn both adjustment screws 1/4 turn counterclockwise.
Turn utility power back on and allow the generator to shut down.

Check and Adjust Engine Governor (Single Cylinder Units) adjustment

Tools: Frequency meter, torque wrench

Loosen the governor clamp bolt.
Hold the governor lever at wide open throttle position.
Rotate the governor shaft clockwise as far as it will go.
Tighten the governor lever clamp bolt to 70 inch-pounds (8 N-m).
Start the generator; let it stabilize and warm up at no-load.
Connect a frequency meter across the generator AC output leads.
Turn the primary adjust screw to obtain a frequency of 61.5 Hz.
Turn the secondary adjust screw to obtain a frequency of 62.5 Hz.

Check and Adjust Valves adjustment

Tools: 10mm allen wrench, flat feeler gauge, torque wrench

Remove the four (4) screws from the rocker cover.
Remove the rocker cover and rocker cover gasket.
Loosen the rocker arm jam nut.
Use a 10mm allen wrench to turn the pivot ball stud.
Check clearance between rocker arm and valve stem with a flat feeler gauge.
Set valve clearance to 0.05-0.1mm (0.002-0.004 in.) cold.
Hold pivot ball stud with allen wrench and tighten rocker arm jam nut to 174 inch pounds.
Recheck valve clearance to make sure it did not change.
Re-install rocker cover gasket, rocker cover and the four screws.

Check and Adjust Voltage Regulator adjustment

Remove the access panel on top of the control panel to access the voltage regulator.
Single cylinder units: with the frequency between 62-63 Hertz, slowly turn the slotted potentiometer until line voltage reads 247-252 volts.
V-twin engine units: with the frequency between 58-59 Hertz, slowly turn the slotted potentiometer until line voltage reads 250-252 volts.

Check/Adjust Valve Clearance adjustment

Tools: feeler gauge, 13mm socket, 5mm hex or TORX T-40 bit, Briggs & Stratton Valve Adjustment Set (Part No. 19465), 5/8 inch spark plug socket

Check valve clearance with the engine cold.
Remove spark plug cables from spark plug terminals; pull on the boot only.
Clean area around spark plugs and remove spark plugs with a 5/8 inch socket.
Turn crankshaft in direction of rotation until piston of cylinder #1 is at Top Dead Center of compression stroke.
Insert wooden dowel into spark plug hole and slowly turn crankshaft until piston moved 1/4 inch (6.0 mm) down the bore.
Remove four screws with washers to release valve cover.
Insert feeler gauge between rocker arm and intake valve stem; verify clearance 0.005 inches (0.127 mm).
If adjustment is needed, obtain Briggs & Stratton Valve Adjustment Set (Part No. 19465).
Place 13mm socket over locknut; insert 5mm hex or TORX T-40 bit through hole to engage adjuster screw.
Rotate socket CCW to loosen locknut; turn adjuster screw CW or CCW to set clearance.
Hold adjuster screw and turn socket CW to tighten locknut to 70 in-lbs (8 Nm).
Check exhaust valve clearance 0.005 inches (0.127 mm) and adjust the same way if needed.
Install valve cover with four screws and tighten to 70 in-lbs (8 Nm) crosswise.
Repeat steps on cylinder #2; install spark plugs and tighten to 180 in-lbs (20 Nm).

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

Voltage	Phase	Connection	Leads	Notes
		23 (White #5)	E	Transfer Control Signal Wire
		Control system interconnections	N1, N2, 0, 15B, 23	Can be run in same conduit as AC power if length < 35 feet and all wiring rated 600V
	1	Connect a 2008 and later load center switch to a pre-2008 air-cooled generator: Wire 0 will not be utilized. Remove battery charger from the transfer switch. Connect N1 (BLU) to N1 (YEL), N2 (YEL) to N2 (YEL), 23 (BRN) to 23 (WHT), 194 (ORG) to 15B (RED) using UL approved wire nuts.	N1, N2, 23, 194, 15B, 0	Battery charger in transfer switch will not be utilized in operation of the generator.
	1	Connect a pre-2008 load center switch to a current or future air-cooled generator: Wire 0 will not be utilized. Connect N1 (BLU) to N1 (YEL), N2 (YEL) to N2 (YEL), 23 (BRN) to 23 (WHT), 194 (ORG) to 15B (RED) using UL approved wire nuts.	N1, N2, 23, 194, 15B, 0	Wire 194 changed to 15B on current model air-cooled generators.
12 VDC		194 (Red #4)	D	DC (+) 12 VDC for Transfer Controls
120	1	Battery charger AC input to generator backed-up 120VAC circuit	120VAC hot, neutral	Connect via wire nuts
120 VAC		T1 (White #3)	B	Fused 120VAC for Battery Charger
120/208	3	parallel wye	S1 through S12; bolted junctions: 4,5,6,10,11,12 to Neutral (00); S1 and S7 to Line E1; S2 and S8 to Line E2; S3 and S9 to Line E3	Voltage Code B. Six coils, twelve leads brought out to AC connection panel.
120/240	1	3-wire	Leads 11 and 44 are hot; junction of Leads 22 and 33 is neutral	Voltage Code A. Stator AC power windings each supply 120 volts AC; in series they supply 240 volts AC.
120/240	1	GENERATOR (STANDBY) source power cables to ATS GENERATOR supply terminals	E1, E2	200A models
120/240	1	Non-essential customer LOAD leads to LSS switch terminals	E1, E2	Load shed switch
120/240	1	UTILITY (NORMAL) power source cables to top of UTILITY SERVICE DISCONNECT circuit breaker	N1, N2	200A models
120/240	1 or 3	delta	Two of six stator coils are double-wound. For 1-phase: connect 240 V loads across Lines E1 and E2; connect 120 V loads across Lines E1 to 00 or E3 to 00.	Voltage Code D.
240	1	Transfer switch terminal lugs: connect utility source hot lines to N1 and N2; connect standby source hot lines (E1, E2) to E1 and E2; connect load lines from T1 and T2 to electrical load circuit; connect UTILITY, STANDBY and LOAD neutral lines to neutral block.	N1, N2, E1, E2, T1, T2	In 1-phase systems with a 2-pole transfer switch.
240 VAC		N1 & N2 (Yellow #1 & #2)	A	Sensing for Utility Dropout and Pickup
DC		0 (Black #3)	C	DC (-) Common Ground Wire

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Aftermarket parts that fit this engine

0G9241T FridayParts $30.99 0G9241 FridayParts $30.99 0D9760 FridayParts $30.99 GSH410 FridayParts $30.99 FP-XP-0033125

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Common questions

What is the oil capacity of the Generac GH-410?

The Generac GH-410 engine has an oil capacity of 1.4 liters.

What is the displacement of the Generac GH-410?

The Generac GH-410 has a displacement of 410.0 liters with 1 cylinders.

Which generators use the Generac GH-410 engine?

The Generac GH-410 powers 1 generator set(s), including Generac 8.1 GN.

How often should you change the oil in the Generac GH-410?

The Generac GH-410 oil change interval is every 250 hours.

What is a common problem with the Generac GH-410 engine?

A commonly reported issue on generators using the Generac GH-410 is: The engine will not crank.. Cause: 1. Fuse blown.. Fix: Correct short circuit condition, replace 7.5A fuse in generator control panel..