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Generac In Line Engine

The Generac In Line is a 1.6 L 4-cylinder naturally aspirated engine rated at 3600 rpm, producing up to 46.23 kW. It powers generator sets from Generac, including the QT 1.5L 20kW, QT 1.6L 20kW and QT 1.6L 25kW. It holds 3.8 L (1.0 gal) of oil and 2 L (0.5 gal) of coolant.

Also known as: Generac In Line

1.6 L

Displacement

Cylinders

3600 rpm

Rated speed

46 kW

Gross power

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

Engine specifications

Oil capacity	3.8 L
Coolant capacity	2.0 L
Displacement	1.6 L
Cylinders	4
Aspiration	Naturally Aspirated
Rated speed	3600 rpm
Gross power	46 kW

Troubleshooting

Symptoms & remedies

Symptom	Cause	Remedy
Engine won’t crank.	1. 15 amp fuse blown. 2. Loose or corroded or defective battery cables. 3. Defective starter contactor. 4. Defective starter motor. 5. Dead or Defective Battery. 6. 5 amp fuse blown.	1. Replace fuse. 2. Tighten, clean or replace battery cables as necessary. 3. Replace contactor.* 4. Replace starter motor.* 5. Remove, change or replace battery. 6. Replace fuse.*
Engine cranks but won't start	1. Out of fuel. 2. Fuel solenoid (FS) is defective 3. Open Wire #14A from Engine Control circuit board. 4. Spark plugs defective. 5. Door on tank not closed.	1. Replenish fuel. 2. Replace solenoid.* 3. Reconnect wire. 4. Clean, regap or replace plugs. 5. Close door on tank.
Engine starts hard, runs rough.	1. Flame arrestor (air cleaner) plugged or damaged. 2. Plugged fuel line. 3. Defective spark plugs. 4. Fuel pressure incorrect.	1. Clean or replace as needed. 2. Unclog fuel line. 3. Clean, regap or replace plugs. 4. Confirm fuel pressure to regulator is as recommended in SPECIFICATIONS.
Engine oil level is low.		Check oil and add oil as needed.
Engine is overheated.		Check cooling system for leaks.
Defective Low Oil Pressure Switch		Replace switch.*
Defective Coolant Temperature Switch		Replace switch.*
Defective Control Module circuit board		Replace board.*
Coolant Level is Low.		Repair leak - Add coolant.
Defective AUTO/OFF/MANUAL switch		Replace switch.*
Open/disconnected wire #15A between AUTO/OFF/MANUAL switch and Control Module circuit board.		Reconnect/close wire.
Engine starts then shuts down.		Defective Control Module circuit board *Contact the nearest Authorized Dealer for assistance.
AUTO/OFF/MANUAL Switch at OFF, engine continues to run		1. Check main line circuit breaker. 2. Check circuit breaker & fuses. 3. Transfer switch set to NORMAL position 4. Generator internal failure. 5. Thermal circuit breaker open.
No AC output from generator.		1. Reset to ON or CLOSED. 2. Reset and replace, if necessary. 3. Set to GENERATOR position. 4. Auto-reset - Wait 5 min. and attempt restart.

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

Common problems

Unit will not start in AUTO with utility loss NOT ACTIVATED
Fix: Refer to activation section in Owner's Manual.
Warning active LOW BATTERY
Fix: Clear alarm. From the MAIN menu on the control panel, navigate to the BATTERY MENU. Contact servicing dealer if battery is GOOD. Replace battery If CHECK BATTERY is displayed.
The engine will not crank
Cause: Fuse blown
Fix: Replace 7.5 amp fuse in generator control panel. Correct short circuit condition if fuse blows again.
Unit consumes large amounts of oil
Cause: Engine over filled with oil
Fix: Adjust oil to correct level.
There is no transfer to standby after utility source failure
Cause: Defective transfer switch coil
Fix: *
The engine cranks but will not start
Cause: Out of fuel
Fix: Replenish fuel. Turn on fuel valve.
Unit shuts down during operation HIGH TEMPERATURE
Fix: Check ventilation around the intake, exhaust and rear of generator. Contact serving dealer if no obstruction is found.
There is no AC output from the generator
Cause: Main line circuit breaker is in the OFF (OPEN) position
Fix: Reset circuit breaker to ON (CLOSED) position.
The generator is set to OFF, but the engine continues to run
Cause: Defective keypad
Fix: *
Unit was running and shuts down, attempts to restart RPM SENSE LOSS
Fix: Clear alarm and remove household loads from the generator. Put back in AUTO and restart. If problem returns, contact servicing dealer to investigate possible fuel issue.
Unit running in AUTO but no power in house
Fix: Check MLCB. Contact servicing dealer if MLCB is in the ON position.
The engine starts hard and runs rough
Cause: Air cleaner plugged or damaged
Fix: Check/replace air cleaner.
Open F1 5 amp fuse F1
Fix: Replace F1 5 amp fuse if fuse blows again.*
Engine won’t crank.
Cause: 1. 15 amp fuse blown. 2. Loose or corroded or defective battery cables. 3. Defective starter contactor. 4. Defective starter motor. 5. Dead or Defective Battery. 6. 5 amp fuse blown.
Fix: 1. Replace fuse. 2. Tighten, clean or replace battery cables as necessary. 3. Replace contactor.* 4. Replace starter motor.* 5. Remove, change or replace battery. 6. Replace fuse.*
Engine starts hard, runs rough.
Cause: 1. Flame arrestor (air cleaner) plugged or damaged. 2. Plugged fuel line. 3. Defective spark plugs. 4. Fuel pressure incorrect.
Fix: 1. Clean or replace as needed. 2. Unclog fuel line. 3. Clean, regap or replace plugs. 4. Confirm fuel pressure to regulator is as recommended in SPECIFICATIONS.

Compiled from service & troubleshooting documentation across every generator set that uses the Generac In Line.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter			059402	500 hr	Amazon eBay $32.00
Fuel filter	Secondary Fuel Regulator		—	240 hr
Oil filter			0A45310244	100 hr	Amazon eBay $24.99 NAPA $9.09
Battery	BCI Group No. 26, 525 CCA @ 0 deg. F		077483		Amazon eBay
Belt	V-BELT 3/8 X 28.9D		0A5586		eBay $29.95 FridayParts $28.15
Coolant		3.0 U.S. gal.	046627		Amazon eBay $15.00
Oil		6.0 qt	—	500 hr
Spark plug	Gap 0.5 - 0.6 mm (0.020 - 0.025 inch)		0A45310275		Amazon eBay $22.57

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

Service intervals

Item	Action	Hours	Months	Notes
Unit (automatic start and transfer to site load)	Test	1 hr		Exercise at least 1 hour looking for leaks, loose connections or components, abnormal operating conditions
Unit (full rated load)	Test	2 hr		Exercise at full rated load at least 2 hours (use load bank if site load insufficient)
Unit	Test	5 hr		5 minute no-load operational run looking for post service problems
Battery electrolyte level (if accessible)	Check	10 hr	1 mo	Adjust as necessary
Battery posts, cables and charger	Check	10 hr	1 mo	Loose connections, corrosion, proper operation; correct as necessary
Natural gas delivery system on gas engine driven units	Check	10 hr	1 mo	Tighten connections as necessary
Unit (Level 1 monthly/10 Hrs)	Check	10 hr	1 mo	Level 1 inspection; disables unit first, then 12 tasks per Service Schedule
Unit wiring	Check	10 hr	1 mo	Loose connections, corrosion and damage; correct as necessary
Engine crankcase oil level	Check	20 hr		Check at least every 20 hours of operation, or prior to use
Automatic start and transfer of unit to site load	Test	30 hr	3 mo	First service — Level 2 break-in; exercise at least 1 hour looking for leaks, loose connections, abnormal conditions
Engine air filter(s)	Replace	30 hr	3 mo	First service — Level 2 break-in
Engine break-in oil and filter	Change	30 hr		First service — First 30 operating hours; break-in oil should be changed after 30 hours
Engine fuel filter(s)	Replace	30 hr	3 mo	Level 2 - on diesel engine driven units; re-prime the fuel system.
Engine fuel filter(s) on diesel engine driven units	Replace	30 hr	3 mo	First service — Level 2 break-in; re-prime the fuel system
Engine oil	Change	100 hr	6 mo	First service — Level 2 break-in
Engine oil filter	Replace	30 hr	3 mo	First service — Service Schedule Level 2 break-in
Engine oil filter(s)	Replace	30 hr	3 mo	First service — Level 2 break-in
Engine spark plugs	Check	30 hr	3 mo	First service — Level 2 - gas engine driven units; clean and re-gap or replace as necessary.
Engine spark plugs on gas engine driven units	Check	30 hr	3 mo	First service — Level 2 break-in; clean and re-gap or replace as necessary
Unit (Level 2 break-in/3 months/30 Hrs)	Check	30 hr	3 mo	First service — Break-in service inspection, performed ONLY ONCE
Unit - 5 minute no-load operational run	Test	30 hr	3 mo	First service — After service, look for post service problems
Unit at full rated load	Test	30 hr	3 mo	First service — Level 2 break-in; exercise at least 2 hours (use load bank if site load is not enough)
engine 'break-in' oil and filter	Change	30 hr		First service — First 30 operating hours
Unit (Level 3 semi-annual/50 Hrs)	Check	50 hr	6 mo	Operational inspection
Cylinder head	Adjust	800 hr		First service — Retorque cylinder head at first 100 operating hours
Engine air filter	Replace	100 hr	12 mo	Service Schedule Level 4, annually
Engine oil and oil filter	Change	100 hr	6 mo	First service — First 100 operating hours; thereafter 100 hours or six months, whichever comes first
Intake and exhaust manifold	Adjust	800 hr		First service — Retorque intake and exhaust manifold at first 100 operating hours
Unit	Other	100 hr	12 mo	First service — Maintenance Level 4 annually; approx 4.0 man-hours
Unit (Level 4 annual/100 Hrs)	Check	100 hr	12 mo	Mid-level inspection
cylinder head	Other	800 hr		First service — Retorque cylinder head - first 100 operating hours
intake and exhaust manifold	Other	800 hr		First service — Retorque intake and exhaust manifold - first 100 operating hours
Coolant Level and Hoses	Check	125 hr	12 mo	Schedule A; also daily if running continuously
Enclosure Louvers	Check	125 hr	12 mo	Schedule A; also daily if running continuously
Fuel Lines	Check	125 hr	12 mo	Schedule A; also daily if running continuously
Lubricating Oil Level and Drain Hose	Check	125 hr	12 mo	Schedule A; also daily if running continuously
Lubricating Oil and Oil Filter	Replace	125 hr	12 mo	First service — Schedule A
Radiator for Clogging	Check	125 hr	12 mo	Schedule A; also daily if running continuously
Air cleaner	Check	500 hr		Every 500 Operating Hours - service air cleaner
Air cleaner	Clean	500 hr		Service air cleaner every 500 operating hours

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	Belt deflection	3/8 - 5/8	in	22 Ibs (10 kgf) force midway between water pump and alternator pulleys
Clearance	Belt deflection	7.6 - 12.7	mm	22 Ibs (10 kgf) force midway between water pump and alternator pulleys
Clearance	Fan belt deflection	3/8 to 5/8 inch (10 to 16 mm)		force of approximately 22 pounds (10 kg) applied midway between pulleys
Clearance	Fan belt deflection	3/8-5/8	inch (10-16 mm)	force of approximately 22 pounds (10 kg) applied midway between pulleys
Gap	Spark Plug Gap (1.5L engines, 25/30 kW)	0.9	mm
Gap	Spark Plug Gap (2.4L engines, 22/27/36/45 kW)	1.07-1.17	mm
Gap	Spark Plug Gap (32/38 kW and 60 kW)	0.71	mm
Gap	Spark plug gap	0.030	inch
Gap	Spark plug gap	0.5 - 0.6	mm (0.020 - 0.025 inch)
Gap	Spark plug gap	0.5 - 0.6 mm (0.020 - 0.025 inch)
Gap	Spark plug gap	0.5-0.6	mm	(0.020-0.025 inch)
Gap	Spark plug gap	0.5-0.6 mm (0.020-0.025 inch)	mm
Gap	Spark plug gap	0.76	mm	set by bending ground electrode
Gap	Spark plug gap	1.07-1.17	mm (0.042-0.046 inch)
Other	Compression Ratio (1.5L)	11:1
Other	Compression Ratio (2.4L)	9.5:1
Other	Engine cooling air flow (inlet air including alternator and combustion air)	1528	ft3/min
Other	Exhaust flow at rated output 60 Hz	249	cfm	60 Hz, rated output
Other	Fan belt deflection	3/8 - 5/8	inch (10 - 16 mm)	Force of approximately 22 pounds (10 kg) applied midway between pulleys
Other	Fan belt deflection	3/8 to 5/8	inch	Force of approximately 22 pounds (10 kg) applied midway between pulleys
Other	Fan belt tension	3/8 to 5/8	inch deflection	22 lb (10 kg) mid-span between pulleys
Other	Fan belt tension (deflection midway between pulleys)	22 pounds (10 kg) applied midway between pulleys deflects belt about 3/8- to 5/8-inch (10 to 16 mm)		cold, engine off
Other	Fan belt tension (deflection)	3/8 - 5/8	inch	force of approximately 22 pounds (10 kg) applied midway between pulleys (10 to 16 mm)
Other	Generator locked rotor KVA available at 35% voltage dip	30	kVA	Single-phase or 208 3-phase
Other	Generator locked rotor KVA available at voltage dip of 35%	34	KVA	Single-phase or 208 3-phase
Other	Governor steady state regulation	± .25	%	Isochronous frequency regulation
Other	Governor steady state regulation	± .25%	%
Other	Governor steady state regulation	±.25	%	Isochronous frequency regulation
Other	HP at rated kW	45	HP	at rated kW
Other	Overcrank crank cycle	15 seconds ON / 7 seconds OFF / 7 seconds ON / 7 seconds OFF / Repeat for 45 seconds; approximately 90 seconds total
Other	Overcrank crank cycle times	15 seconds ON / 7 seconds OFF / 7 seconds ON / 7 seconds OFF / repeat for 45 seconds (approximately 90 seconds total)
Other	Steady State Regulation	+/- 0.25%
Other	Telephone interference factor (TIF)	< 50
Other	Total Harmonic Distortion	<5%
Other	Total harmonic distortion	< 5	%
Other	Voltage regulator regulation	± 1%	%	single-phase sensing
Pressure	LP Fuel Pressure	11 - 14	" WC
Pressure	Low oil pressure switch	8	psi	contacts close below this pressure
Pressure	Low oil pressure switch setpoint	8	psi	contacts close below this pressure
Pressure	Low oil pressure switch trip point	8	psi
Pressure	Maximum pressure at fuel shutoff solenoid (natural gas)	14	inches water column
Pressure	NG Fuel Pressure	3.5 - 14	" WC
Pressure	Natural gas / LP fuel pressure at fuel shut-off solenoid	5 in. - 14 in.	Water Column (0.18 to 0.5 psi)	operating
Pressure	Natural gas delivery pressure to carburetor	approximately five	inches water column
Pressure	Operating fuel pressure	5 - 14	inches water column	Natural gas and propane vapor (0.18 to 0.5 psi)
Pressure	Operating fuel pressure	5 in. - 14 in.	water column	Natural gas and propane vapor
Pressure	Operating fuel pressure	5 to 14	inches water column
Pressure	Operating fuel pressure	5" - 14"	H2O
Pressure	Optimum pressure at fuel shutoff solenoid	11	in. water column	Natural gas (0.4 psi)
Pressure	Optimum pressure at fuel shutoff solenoid (natural gas)	11	inches water column
Speed	Fan Speed (rpm)	1,980 / 2,484 / 1,500 / 1,865 / 2,100	rpm
Speed	Fan speed	2550	rpm
Speed	Rated synchronous RPM	1800	rpm	60 Hz
Speed	Rated synchronous RPM	3600	rpm	60 Hz
Speed	Rated synchronous RPM	60 Hz, 3600	rpm
Speed	Rated synchronous RPM (60 Hz)	3600	rpm	60 Hz
Speed	Rated synchronous RPM 60 Hz	3600	rpm	60 Hz
Speed	Rated synchronous speed	3600	rpm	60 Hz
Speed	Steady State Regulation (Governor)	±0.25%
Speed	Steady state frequency regulation	± 0.25		isochronous governor

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	50-50 low silicate ethylene glycol base anti-freeze and deionized water			2.0 U.S. gal	Do not use chromate base rust inhibitor or high silicate additives
Coolant	50-50 mixture of low silicate ethylene glycol base anti-freeze and deionized water			3.0 U.S. gal	Add recommended 50-50 mixture; do not use chromate base rust inhibitor
Coolant	50/50 ethylene glycol	Generac 50/50 ethylene glycol type coolant		9.5 liters	Use demineralized or distilled water; do not use propylene glycol. Coolant mix 40-60% volume.
Coolant	50/50 low silicate ethylene glycol base anti-freeze and deionized water			2.0 U.S. gal	Do not use chromate base rust inhibitor; do not use high silicate anti-freeze boosters or additives
Coolant	Half low silicate ethylene glycol base anti-freeze and deionized water (50-50 mixture)	Low silicate anti-freeze, deionized water		2.0 U.S. gal.	Do not use chromate base rust inhibitor with ethylene glycol; do not use high silicate anti-freeze boosters/additives; soluble oil inhibitor NOT recommended
Coolant	Mixture of half low silicate ethylene glycol base anti-freeze and deionized water (50-50)	Low silicate anti-freeze only; high quality rust inhibitor may be added		2.0 U.S. gal	Do not use chromate base rust inhibitor with ethylene glycol base anti-freeze; do not use high silicate anti-freeze boosters or additives; soluble oil inhibitor NOT recommended
Coolant	Peak Fleet-Charge 50/50 ethylene glycol		-20°C to 48°C	2.8 gal	Use demineralized or distilled water base
Engine oil	15W-40	high-quality detergent oil classified "For Service CC, SD, SE, SF"		4.0 U.S. qts	Filled with 15W-40 at the factory
Engine oil	15W-40 (factory fill); Above 80° F (27° C): SAE 30W or 15W-40; 32° to 80° F (0° to 27° C): SAE 20W-20 or 15W-40; Below 32° F (0° C): 5W-30 synthetic	High-quality detergent oil classified "For Service CC, SD, SE, SF"		4.0 U.S. qts. (3.8 liters)	Cold Weather Start Kit recommended below 32° F; 6 qt. pack 5W-30 synthetic oil included in kit 0F6148
Engine oil	5W-20	Generac proprietary 5W-20 Synthetic (after 30 hour break-in)		3.8 liters	Factory filled with 5W-20; 60 kW capacity 5.25 quarts (5 liters). Do not use special additives.
Engine oil	5W-30 synthetic		below 0°C		For temperatures below 32°F (0°C); Cold Weather Start Kit recommended
Engine oil	5W-30 synthetic oil		below 0°C	4.0 U.S. qts	For temperatures below 32° F (0° C); use optional Cold Weather Start Kit (part number 0F6148)
Engine oil	SAE 20W-20 or 15W-40		0°C to 27°C		For 32° to 80°F (0° to 27°C)
Engine oil	SAE 30W or 15W-40	For Service CC, SD, SE, SF	above 27°C	4.0 U.S. qts	For temperatures above 80°F (27°C); factory fill is 15W-40
Fuel		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 5 to 14 inches water column (0.18 to 0.5 psi) for both natural gas and liquid propane. Optimum pressure at fuel shutoff solenoid is 11 inches water column (0.4 psi).
Fuel	LP (liquid propane) gas / propane vapor	At least 2,520 Btus per cubic foot			Required pressure 5 to 14 inches water column (0.18 to 0.5 psi); propane vaporizes readily at temperatures as low as -20° F (-29° C); butane reverts to liquid below 32° F (0° C)
Fuel	LP gas	at least 2,520 Btus per cubic foot			Required fuel pressure 5 to 14 inches water column
Fuel	LP gas Btu content at least 2,520 Btus per cubic foot				Liquid propane required pressure 5 to 14 inches water column (0.18 to 0.5 psi)
Fuel	Liquid propane (LP) / propane vapor	Btu content of at least 2,520 Btus per cubic foot; required pressure 5 in. to 14 in. water column (0.18 to 0.5 psi)			Propane vaporizes readily down to -20° F (-29° C)
Fuel	Natural Gas	at least 1,000 Btus per cubic foot			Required fuel pressure 5 to 14 inches water column
Fuel	Natural Gas (Btu content at least 1,000 Btus per cubic foot) or LP gas (at least 2,520 Btus per cubic foot)				Operating fuel pressure 5 in. - 14 in. water column
Fuel	Natural Gas (min. 1,000 Btus per cubic foot) or LP gas / Propane Vapor (min. 2,520 Btus per cubic foot)	Required fuel pressure 5 to 14 inches water column (0.18 to 0.5 psi)			All models configured for natural gas or LP vapor from factory; Port 1 NG only, Port 2 LP vapor only; no dual fuel provision
Fuel	Natural Gas at least 1,000 BTUs per cubic foot; LPV at least 2,520 BTUs per cubic foot			250.0 gallons	Minimum LP tank size 250 gallons (946 liters) if converting to LPV from NG
Fuel	Natural Gas or Propane Vapor	at least 1,000 Btu per cubic foot natural gas; at least 2,520 Btu per cubic foot LP gas			Operating fuel pressure 5 in. - 14 in. water column (0.18 to 0.5 psi)
Fuel	Natural gas	Btu content of at least 1,000 Btus per cubic foot; required pressure 5 in. to 14 in. water column (0.18 to 0.5 psi)			Optimum pressure at fuel shutoff solenoid is 11 inches water column (0.4 psi)
Fuel	Natural gas (min 1,000 Btu/ft3) or LP gas (min 2,520 Btu/ft3)				Required fuel pressure 5 to 14 inches water column (0.18 to 0.5 psi)
Fuel	Natural gas Btu content at least 1,000 Btus per cubic foot				Required fuel pressure 5 to 14 inches water column (0.18 to 0.5 psi)
Fuel	Natural gas, propane vapor				Operating fuel pressure 5” - 14” H2O
Fuel	Ultra Low Sulfur Diesel		below 40°C		Mechanical engine-driven pump, 5 micron filter (15/20/30 kW), 10 micron filter (48/50 kW)
Gear oil	SAE 90				Generator gearbox, if equipped

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
HIGH TEMPERATURE	High Temperature	Engine coolant temperature exceeds limit	Shutdown
LOW OIL PRESSURE	Low Oil Pressure	Oil pressure below acceptable level	Warning
NOT ACTIVATED	Not Activated	Unit will not start in AUTO with utility loss	Info
OVERCRANK	Overcrank	Engine overcrank fault	Warning
OVERLOAD	Overload	Unit overloaded, shuts down during operation	Shutdown
RPM SENSE LOSS	RPM Sense Loss	Loss of engine RPM signal	Shutdown

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

Procedures

Check and Adjust Accessory / Drive Belt adjustment

Tools: Belt deflection gauge

Inspect belt for cracks, fraying, excessive wear or other damage.
Verify belt is free of grease and oil; replace if contaminated.
Using a suitable gauge, apply 22 Ibs (10 kgf) force midway between water pump and alternator pulleys.
Loosen DC alternator tension bracket screw.
Rotate alternator outward to reduce belt deflection.
Rotate inward to increase belt deflection.
Tighten DC alternator tension bracket screw to 17-22 ft-lbs (23-30 Nm).
Recheck belt deflection and repeat steps as necessary.

Fuel Conversion Procedure from NG to LPV adjustment

⚠ Fuel conversion software is password protected

⚠ Failure to convert both hardware and software violates EPA regulations

Tools: Flat blade screwdriver, Pipe sealant

Turn off the main gas supply.
Remove battery negative cable (black) from battery negative (-) terminal.
Remove carburetor fuel hose from outlet port.
Remove screw at front of power wire connector and pull connector from fuel solenoid.
Expand spring clamp on fuel enrichment hose and remove from hose barb.
Remove black pipe assembly from outlet port; remove fuel solenoid assembly if clearance is insufficient.
Rotate NG fuel jet counterclockwise to remove from outlet port.
Rotate LP fuel jet counterclockwise to remove from jet keeper port.

Reconfiguring the Fuel System (NG to LP vapor) adjustment

⚠ Serious injury or damage may occur if not configured properly. Please consult an Authorized Service Dealer with any questions.

Turn the main gas supply off.
Remove the carburetor fuel hose from the outlet port (Port 1) of the demand regulator.
Remove the brass hose fitting from the outlet port (Port 1).
Remove pipe plug from Port 2.
Install brass hose fitting into Port 2.
Install pipe plug into Port 1.
Connect carburetor gas hose to brass fitting.
Tighten all clamps and plugs.
Make sure fuel supply is of proper pressure and type for configuration.
Reverse the procedure to convert back to natural gas.
The Dip switch inside the control panel must be in the LP or NG position when switching fuels.

Spark Plugs - Check Gap and Replace adjustment

⚠ Do not blast the spark plugs to clean.

Tools: Wire brush, Wire feeler gauge

Clean the area around the base of the spark plugs to keep dirt and debris out of the engine. Clean by scraping or washing using a wire brush and commercial solvent. Do not blast the spark plugs to cle
Remove the spark plugs and check the condition.
Replace the spark plugs if worn or if reuse is questionable.
Check the spark plug gap using a wire feeler gauge.
Adjust the gap to 0.5-0.6 mm (0.020-0.025 inch) by carefully bending the ground electrode.

Test Auxiliary Shutdown Switch Operation diagnostic

⚠ Auxiliary shutdown switches are not a primary means to shut down generator under normal conditions

Verify auxiliary shutdown switches are ON (I).
Press MANUAL key on control panel keypad to start engine.
With engine running, set one auxiliary shutdown switch to OFF (O); engine should shut down immediately.
If engine stops, set switch to ON (I), clear alarm, and restart to verify normal operation.
Verify operation of second auxiliary switch.
If engine does not stop, contact an IASD.

Install Battery installation

⚠ Always connect positive battery cable first to avoid spark

Loosen the two screws with nylon washers to release hold-down clamp from battery tray.
Install battery onto tray.
Install the two screws with nylon washers to secure hold-down clamp to battery tray.
Install positive battery cable (red) to positive (+) battery terminal.
Install negative battery cable (black) to negative (-) battery terminal.

Preparation for Start-up installation

⚠ Before working on the generator, ensure the AUTO/OFF/MANUAL switch is in the OFF position and the 120VAC supply to the battery charger is switched OFF.

Tools: Manometer

Ensure that the 120VAC circuit breaker to the battery charger is open.
Remove the fuse from the control panel (15 Amp ATO fuse).
Connect the battery cables to the battery. Attach negative battery cable last.
Close the 120VAC circuit breaker to the battery charger.
Measure the voltage at the battery before and after the charger is turned on.
Verify all AC electrical connections are tight at the circuit breaker and transfer switch.
Check all hoses clamps fittings for leaks or damage.
Open the valve to the engine fuel line.
Bleed the fuel system of air (necessary for long fuel lines).
Open the generator main line circuit breaker.
Connect a manometer to the gas line and record the static pressure.
Insert the fuse into the control panel.
Move the AUTO/OFF/MANUAL switch to the MANUAL position. The engine should now crank and start.

Preparation for Start-up (Start-up Checklist) installation

⚠ Before working on the generator, ensure the AUTO/OFF/MANUAL switch is in the OFF position.

⚠ Ensure the 120VAC supply to the battery charger is switched OFF.

Tools: manometer

Ensure that the 120VAC circuit breaker to the battery charger is open.
Remove the fuse from the control panel.
Connect the battery cables to the battery; attach negative battery cable last.
Close the 120VAC circuit breaker to the battery charger.
Measure the voltage at the battery before and after the charger is turned on.
Verify all AC electrical connections are tight at the circuit breaker and transfer switch.
Check all hoses, clamps and fittings for leaks or damage.
Verify the AUTO/OFF/MANUAL switch is in the OFF position.
Open the valve to the engine fuel line and bleed the fuel system of air.
Open the generator main line circuit breaker.
Connect a manometer to the gas line and record the static pressure.
Insert the fuse into the control panel.
Move the AUTO/OFF/MANUAL switch to the MANUAL position; the engine should crank and start.

Reconfiguring the Fuel System (NG to LP) installation

⚠ Serious injury or damage may occur if not configured properly. Please consult an Authorized Dealer with any questions.

Turn the main gas supply off.
Remove the carburetor fuel hose from the outlet port (Port 1) of the demand regulator.
Remove the brass hose fitting from the outlet port (Port 1).
Remove pipe plug from Port 2.
Install brass hose fitting into Port 2.
Install pipe plug into Port 1.
Connect carburetor gas hose to brass fitting.
Tighten all clamps and plugs.
Make sure fuel supply is of the proper pressure and type for configuration.
Reverse the procedure to convert back to natural gas.
Set the dip switch inside the control panel to the LP or NG position.

Start-up Inspection installation

Check voltage at the generator terminals.
For 3-phase units, check phase rotation at the transfer switch terminals.
Check for coolant, fuel, oil, and exhaust leaks.
Close the generator's main line circuit breaker.
Turn the generator set off.
Connect the UTILITY supply to the transfer switch.
Set the AUTO/OFF/MANUAL switch to AUTO.
Disconnect utility power to verify the engine starts and transfers to load.
Run at least 15 minutes on generator power.
Reconnect utility power.
Install all covers, access plates and door panels.

Battery Maintenance maintenance

⚠ Storage batteries give off explosive hydrogen gas.

⚠ Battery electrolyte fluid is an extremely corrosive sulfuric acid solution.

⚠ Do not use jumper cables or booster battery to crank and start the generator engine.

Tools: Battery hydrometer

Inspect the battery posts and cables for tightness and corrosion; tighten and clean as necessary.
Check the battery fluid level of unsealed batteries; fill with distilled water only.
Have the state of charge and condition checked with an automotive-type battery hydrometer.

Battery Replacement maintenance

⚠ Disconnect battery ground terminal before working on battery or battery wires

⚠ Always connect positive battery cable first

Remove negative battery cable (black) from negative (-) battery terminal.
Remove positive battery cable (red) from positive (+) battery terminal.
Install rubber protective cover over positive (+) battery terminal.
Loosen two screws with nylon washers to release battery hold-down clamp from battery tray.
Grasp battery strap and lift battery from battery tray.
Remove rubber protective cover from positive (+) battery terminal.
Set new battery onto battery tray and secure hold-down clamp.
Install positive cable then negative cable.

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
120/208	3	Three phase	RD015, RD020, RD030, RD050
120/208	3-phase	Stator power winding connections - 3-phase (Y)	6	Rated voltage between circuit breaker terminals E1-E2, E1-E3 and E2-E3 is 208V; terminal to neutral 120V
120/208	3-phase	Y	6-lead	Figure 7.3 - Stator Power Winding Connections. Rated 208V L-L, 120V L-N.
120/208V	3	3-phase alternator, "Y" configuration, 6 lead	6	Rated voltage between circuit breaker terminals E1-E2, E1-E3, E2-E3; rated voltage to neutral 120V
120/208V	3	Stator power winding connections - 3-phase, Y configuration	6	Rated voltage between circuit breaker terminals E1-E2, E1-E3 and E2-E3 is 208V; between each terminal and neutral 00 is 120V
120/208V	3	Y	6	Stator power winding connections (Figure 7.3)
120/208V	3	Y (wye) - Stator Power Winding Connections, 3-phase, 120/208V	6 lead (S1-S6, E1-E3, neutral 00)	Rated voltage between circuit breaker terminals E1-E2, E1-E3 and E2-E3 is 208V; between each terminal and neutral point 00 is 120V. 85 Amps, CB size 100.
120/208V	3	Y configuration (6 lead)	6	Rated voltage between breaker terminals E1-E2, E1-E3, E2-E3 is 208V; between each terminal and neutral 00 is 120V. Voltage code G.
120/208V	3-phase	0.8 pf	4 wire	36 kW LPG / 35 kW NG; 125 A LPG / 121 A NG; CB size both 150
120/208V	3-phase	Y configuration, 6 lead	6	Rated voltage between circuit breaker terminals E1-E2, E1-E3 and E2-E3 is 208V; between each terminal and neutral point 00 is 120V
120/240	1	Single phase	RD015, RD020, RD030, RD048
120/240	1-phase	4-lead single-phase stator, connected at factory to main circuit breaker (voltage code A)	4	Rated voltage between circuit breaker terminals 240V; between each terminal and neutral 120V
120/240	1-phase	Four-lead, single-phase stator - connected at the factory to the main circuit breaker (voltage code A)	4-lead	Rated 240V between circuit breaker terminals; 120V between each terminal and neutral point 00. 60 Hz.
120/240	3	Three phase	RD015, RD020, RD030, RD048, RD050
120/240V	1	4-lead, single-phase stator; factory connected to main circuit breaker	4	Rated voltage between each circuit breaker terminal is 240V; between each terminal and neutral point 00 is 120V. Voltage code A.
120/240V	1	Four-lead, single-phase stator (voltage code "A")	4-wire	Rated voltage between each circuit breaker terminal is 240V; between each circuit breaker terminal and neutral point 00 is 120V. 104 Amps, CB size 125.
120/240V	1	Four-lead, single-phase stator; voltage code "A"	4	Rated 240V between each circuit breaker terminal; 120V between each terminal and neutral point 00
120/240V	1	Four-lead, single-phase stator; windings factory-connected to the main circuit breaker	4	Rated voltage between each circuit breaker terminal is 240V; between each terminal and neutral point 00 is 120V
120/240V	1	Voltage code A; four-lead, single-phase stator; windings factory-connected to main circuit breaker	4	Rated voltage between circuit breaker terminals 240V; between each terminal and neutral 120V
120/240V	1-phase	1.0 pf		36 kW LPG / 35 kW NG; 150 A LPG / 146 A NG; CB size both 175
120/240V	1-phase	Four-lead, single-phase stator, voltage code A; windings connected at factory to main circuit breaker	4	Rated voltage between each circuit breaker terminal is 240V; between each terminal and neutral point 00 is 120V
120/240V	3-phase	0.8 pf	4 wire	36 kW LPG / 35 kW NG; 108 A LPG / 105 A NG; CB size both 125
208	3	Stator power winding connections - 3-phase, 120/208V (6 lead), 'Y' configuration	6	Rated voltage between circuit breaker terminals E1-E2, E1-E3 and E2-E3 is 208V; between each terminal and neutral point 00 is 120V. Output table: 25 kW, 120/208V, 3-phase, 0.8 pf, 87 Amp, 100 Amp circuit breaker (3 pole, 240V).
208	3-phase	Circuit breaker size table (Figure 1)		KW 25, 208 3-phase, 100 Amps, lug size #4 to 1/0.
208 (3 Ø)	3	Circuit breaker size 100 A; lug size #4 to 1/0		25 kW
208 3 Ø	3-phase	Generator main line circuit breaker / lug size		KW 20, Amps 80, Lug size #4 to 1/0
208V	3	Circuit breaker lug size #4 to 1/0		KW 20, Volts/Amps 208 3-phase, Circuit Breaker Size 80
208V / 3-phase	3	Circuit breaker 80A, lug size #4 to 1/0		20 kW
208V, 3-phase	3	Circuit breaker size 100 A, lug size #4 to 1/0		25 kW / 208V / 100A
240	1	Four-lead, single-phase stator; windings factory connected to main circuit breaker (voltage code 'A', 240V, 1-phase, 60 Hz)	4	Rated voltage between each circuit breaker terminal is 240V; between each circuit breaker terminal and neutral point 00 is 120V. Output table: 25 kW, 120/240V, 1-phase, 1.0 pf, 104 Amp, 125 Amp circuit breaker (2 pole, 240V).

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

Common questions

What is the oil capacity of the Generac In Line?

The Generac In Line engine has an oil capacity of 3.8 liters.

What is the displacement of the Generac In Line?

The Generac In Line has a displacement of 1.6 liters with 4 cylinders.

Which generators use the Generac In Line engine?

The Generac In Line powers 27 generator set(s), including Generac In Line, Generac QT 1.5L 20kW, Generac QT 1.6L 20kW, Generac QT 1.6L 25kW, Generac QT022.

How often should you change the oil in the Generac In Line?

The Generac In Line oil change interval is every 500 hours.

What is a common problem with the Generac In Line engine?

A commonly reported issue on generators using the Generac In Line is: Unit will not start in AUTO with utility loss. Fix: Refer to activation section in Owner's Manual..

Generac In Line Engine

Engine specifications

Generator sets powered by this engine

Troubleshooting

Symptoms & remedies

Common problems

Maintenance schedule

Service intervals

Service specifications

Recommended fluids

Fault codes

Procedures

Voltage reconnection

Common questions