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Honda iGX390 Engine

The Honda iGX390 is a 0.39 L engine rated at 3600 rpm. It powers generator sets from Honda, including the EB5000, EB6500 and EM5000SX. It holds 1.1 L (0.3 gal) of oil.

Also known as: Honda iGX390

0.389 L
Displacement
3600 rpm
Rated speed
1.1 L
Oil capacity

Engine specifications

Oil capacity1.1 L
Displacement0.389 L
Rated speed3600 rpm

Common problems

6
  • When the engine will hot start
    Fix: 1. Is the engine switch on? 2. Does the oil alert lamp flash when the starter is pulled? 3. Is there enough fuel? 4. Are all loads disconnected from the AC receptacles? 5. Is there a spark at the spark plug? a. Remove the spark plug cap, Clean any dust from around the spark plug base, then remove the spark plug. b. Install the spark plug in the plug cap. c. Turn the engine switch on. d. Grounding the side electrode to any engine ground, pull the recoil starter to see if sparks jump across the gap. e. If any fuel has been spilled, make sure the area is dry before testing the spark plug. Fuel vapor or spilled fuel may ignite. Perform this test in a well-ventilated area. f. If there are no sparks, replace the plug. g. If the new spark plug does not spark, take the generator to an authorized Honda dealer.
  • The engine stops and will not restart.
    Fix: Check the engine oil level (see page 40) before troubleshooting in other areas.
  • Running the engine with persistent spark knock or pinging can cause engine damage.
    Fix: Running the engine with persistent spark knock or pinging is misuse, and the Distributor’s Limited Warranty does not cover parts damaged by misuse.
  • Occasionally you may hear a light ‘‘spark knock’’ or ‘‘pinging’’ (metallic rapping noise) while operating under heavy loads.
    Fix: This is no cause for concern. If spark knock or pinging occurs at a steady engine speed, under normal load, change brands of gasoline. If spark knock or pinging persists, see an authorized Honda generator dealer.
  • Engine speed becomes abnormal.
    Fix: The engine will automatically stop if the engine speed becomes abnormal.
  • Abnormal voltage is detected during generation.
    Fix: The engine will automatically stop during generation when it detects abnormal voltage.

Compiled from service & troubleshooting documentation across every generator set that uses the Honda iGX390.

Service intervals

13
ItemActionHoursMonthsNotes
Engine oilChange300 hr12 moFirst service — First month or 20 Hrs (page 67)
Air cleanerClean50 hr3 moService more frequently when used in dusty areas (1)
Sediment cupClean100 hr6 moPage 58
Fuel tank and filterClean300 hr12 mo(2)
Spark arresterClean300 hr12 moEvery year or 300 Hrs; also must be serviced every 100 hours (page 71)
Spark plugAdjust300 hr12 moCheck-adjust every year or 300 Hrs (page 69)
Spark plugReplace300 hr12 moEvery year or 300 Hrs (page 69)
Valve clearanceAdjust300 hr12 moCheck-adjust every year or 300 Hrs; by servicing dealer (2)
Combustion chamberClean1000 hrAfter every 1,000 Hrs (2)
CanisterCheck24 moEvery 2 years (2)
Charge tubeCheck24 moEvery 2 years (2)
Fuel tubeCheck24 moEvery 2 years (replace if necessary) (2)
Purge tubeCheck24 moEvery 2 years (2)

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

31
TypeItemValueUnitCondition
GapSpark plug electrode gap0.028–0.031 in (0.7–0.8 mm)mm
GapSpark plug gap0.028-0.031in (0.70-0.80 mm)
GapSpark plug gap0.028–0.031in (0.7–0.8 mm)
OtherCompression ratio8.2:1
OtherCrank duration3-3-4-5secper automatic attempt sequence
OtherEnclosure dimensions85x58x33mm
OtherLength of cable2m
OtherMax. Standby Current9.8mA @ 12 V
OtherNumber of attempts4automatic starting attempts
OtherPause between each automatic attempt10sec
SpeedEngine speed3,600rpm
SpeedEngine speed protection limit (DAVR self-diagnosis)4140rpmabnormal voltage/speed sustained longer than 3 seconds
TemperatureOperating Temperature Range-30 to +70°C
TorqueHandle installation17–22 lbf·ft (24–29 N·m, 2.4–3.0 kgf·m)N·m
TorqueHandle installation flange bolts19.5 lbf·ft (26.5 N·m, 2.7 kgf·m)lbf·ft
TorqueHanger kit flange bolts19.5 lbf·ft (26.5 N·m, 2.7 kgf·m)lbf·ft
TorqueHanger kit installation17–22 lbf·ft (24–29 N·m, 2.4–3.0 kgf·m)N·m
TorqueOil drain plug (12×15 mm)16.3 lbf·ft (22.1 N·m, 2.25 kgf·m)lbf·ft
TorqueOil drain plug (12×15 mm)16.6 lbf·ft (22.5 N·m, 2.25 kgf·m)N·m
TorqueSpark plug13.0 lbf·ft (17.7 N·m, 1.8 kgf·m)lbf·ft
TorqueSpark plug13.3 lbf·ft (18 N·m, 1.8 kgf·m)N·m
TorqueWheel kit flange bolts19.5 lbf·ft (26.5 N·m, 2.7 kgf·m)lbf·ft
TorqueWheel kit installation17–22 lbf·ft (24–29 N·m, 2.4–3.0 kgf·m)N·m
Valve clearanceValve clearance EX0.20 ± 0.02mmcold
Valve clearanceValve clearance EX0.20±0.02mmcold
Valve clearanceValve clearance EX0.20±0.02 mmmmcold
Valve clearanceValve clearance IN0.15 ± 0.02mmcold
Valve clearanceValve clearance IN0.15±0.02mmcold
Valve clearanceValve clearance IN0.15±0.02 mmmmcold
VoltageDC supply12VDCgenerator battery
VoltageVoltage regulation stability (DAVR)within 1%standard operation

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

FluidGradeStandardAmbientCapacityNotes
Engine oilSAE 10W-30API service category SJ or later (or equivalent)1.1 LMaximum oil capacity 1.2 US qt (1.1 L); 4-stroke automotive detergent oil; other viscosities per ambient temperature chart
Engine oilSAE 10W-30 (other viscosities per ambient temperature chart)API service classification SJ or higher1.1 LNon detergent and 2-stroke oils are not recommended
FuelRegular unleaded gasoline, pump octane rating 86 or higherNo more than 10% ethanol (E10) or 5% methanol by volume23.5 LFuel tank capacity 6.21 US gal (23.5 L)
Fuelunleaded gasoline, pump octane rating 86 or higher17.0 LDo not fill above the shoulder of the fuel strainer; oxygenated fuels allowed up to 10% ethanol, 15% MTBE, 5% methanol by volume

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

Procedures

12
Setting up 10 sec start delay adjustment

⚠ 10 sec start delay is used in combination with an ATS panel to prevent multiple short start-stop commands coming from the ATS panel while the mains is unstable during blackout.

  1. Open the controller cover and locate the red dip switch (S-DELAY).
  2. Use your finger to move the dip switch 1 to ON position.
  3. Replace the cover and tighten screws.
GFCI Operation Check (System ①) diagnostic

⚠ A faulty GFCI system will not provide proper protection against electric shock.

⚠ If the GFCI system fails the test, the generator must be repaired by an authorized Honda servicing dealer before use.

  1. Unplug all tools and appliances from the generator.
  2. Start the engine.
  3. Turn OFF the Auto Throttle switch.
  4. Turn the AC circuit breaker to the ON position.
  5. Press the TEST button: the RESET button should pop out and the AC circuit breaker should switch to OFF.
  6. Press the RESET button: it should stay in, flush with its base plate.
  7. With the RESET button in and the engine running, turn the AC circuit breaker to ON; it should remain ON.
GFCI Operation Check (System ②) diagnostic

⚠ If the red indicator starts to blink continuously, contact an authorized Honda generator dealer.

  1. Unplug all tools and appliances from the generator.
  2. Start the engine.
  3. Turn OFF the Auto Throttle switch.
  4. Turn the AC circuit breaker to the ON position; the green indicator should light continuously.
  5. Press the TEST button: the RESET button will pop out and the green indicator will go off.
  6. Press the RESET button: the green indicator will light continuously.
2 Wheel Kit Installation installation
  1. Install the two wheels on the axle shaft.
  2. Install the axle assembly on the generator using four bolts and nuts.
  3. Install the two stands using four bolts and nuts.
  4. Install right and left handles on the generator upper frame using brackets and six bolts.
4 Wheel Kit Installation installation

⚠ Install the shaft with the wheel stopper facing the engine side.

  1. Install the four wheels on the axle shaft.
  2. Install the axle assembly on the generator using four bolts and nuts.
Handle Installation installation

⚠ Do not add fuel or oil before tipping the generator.

Tools: 12 mm wrench (2), pliers

  1. Install the handle holder assembly on the generator upper frame using the 8×18 mm flange bolts.
  2. Install the handle assembly on the upper frame pipe using 8×16 mm flange bolts, handle bush A, handle bush B, and handle lower bracket.
  3. Torque to 19.5 lbf·ft (26.5 N·m, 2.7 kgf·m).
  4. Check that the handle folds smoothly and does not hang down by its own weight.
Hanger Kit Installation installation

Tools: 12 mm wrench (2)

  1. Position the hanger at the generator's balance point.
  2. Fit the end tabs of the hanger through the bracket slots.
  3. Bolt the brackets to the hanger and tighten securely.
  4. Torque to 19.5 lbf·ft (26.5 N·m, 2.7 kgf·m).
Wheel Kit Installation installation

Tools: 12 mm wrench (2), pliers

  1. Install the two stands on the under frame using four 8×16 mm flange bolts.
  2. Install the two wheels on the axle shaft using the washers and split pins; bend the pins.
  3. Install the axle assembly using four 8×16 mm flange bolts and 8 mm flange nuts.
  4. Torque to 19.5 lbf·ft (26.5 N·m, 2.7 kgf·m).
Air Cleaner Element Cleaning maintenance

⚠ Do not twist the foam filter when squeezing.

⚠ Prevent dirt from entering the air duct that leads to the carburetor.

  1. Clean the foam air filter in warm soapy water, rinse, and allow to dry thoroughly, or clean in non-flammable solvent and dry.
  2. Dip the foam air filter in clean engine oil, then squeeze out all excess oil.
  3. Wipe dirt from the air cleaner housing and cover using a moist rag.
Air Cleaner Service maintenance

⚠ Never run the generator without the air filter.

⚠ Engine will smoke during initial startup if too much oil is left in the air filter.

  1. Unsnap the air cleaner cover clips, remove the cover, and remove the element.
  2. Wash the air filter in household detergent and warm water, or nonflammable/high flashpoint solvent; rinse thoroughly.
  3. Allow the air filter to dry thoroughly.
  4. Soak the air filter in clean engine oil and squeeze out the excess oil.
  5. Reinstall the air cleaner element and the cover.
Draining the Fuel Tank and Carburetor maintenance

⚠ Gasoline is highly flammable and explosive; keep heat, sparks, and flame away.

⚠ Handle fuel only outdoors.

Tools: funnel

  1. Turn the fuel valve lever to the OFF position.
  2. Place a suitable gasoline container below the carburetor.
  3. Loosen the carburetor drain screw and drain the gasoline.
  4. Tighten the carburetor drain screw securely.
  5. Place a container below the sediment cup and remove the sediment cup.
  6. Turn the fuel valve lever to ON and drain the fuel from the tank.
  7. Install the sediment cup and a new O-ring.
Engine Oil Change maintenance

⚠ Wash your hands with soap and water after handling used oil.

⚠ Dispose of used oil properly.

  1. Place a suitable container below the engine.
  2. Remove the oil filler cap/dipstick, 12×15 mm drain plug, and sealing washer.
  3. Allow the used oil to drain completely.
  4. Reinstall the drain plug and a new sealing washer; tighten securely.
  5. Fill to the upper limit mark with recommended oil.
  6. Reinstall the oil filler cap/dipstick securely.

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 Honda iGX390?

The Honda iGX390 engine has an oil capacity of 1.1 liters.

What is the displacement of the Honda iGX390?

The Honda iGX390 has a displacement of 0.389 liters.

Which generators use the Honda iGX390 engine?

The Honda iGX390 powers 3 generator set(s), including Honda EB5000, Honda EB6500, Honda EM5000SX.

What is a common problem with the Honda iGX390 engine?

A commonly reported issue on generators using the Honda iGX390 is: When the engine will hot start. Fix: 1. Is the engine switch on? 2. Does the oil alert lamp flash when the starter is pulled? 3. Is there enough fuel? 4. Are all loads disconnected from the AC receptacles? 5. Is there a spark at the spark plug? a. Remove the spark plug cap, Clean any dust from around the spark plug base, then remove the spark plug. b. Install the spark plug in the plug cap. c. Turn the engine switch on. d. Grounding the side electrode to any engine ground, pull the recoil starter to see if sparks jump across the gap. e. If any fuel has been spilled, make sure the area is dry before testing the spark plug. Fuel vapor or spilled fuel may ignite. Perform this test in a well-ventilated area. f. If there are no sparks, replace the plug. g. If the new spark plug does not spark, take the generator to an authorized Honda dealer..