| Disconnecting Set from RV Systems | | 1. First disconnect the negative (-) battery cable from the baitery and then disconnect the battery cables from the genset. 2. Disconnect the remote control wiring harness connector at the genset. 3. Disconnect the generator output wiring and conduit from the power distribution panel or box on the vehicle. Tag all wires to make reconnections easier. 4. Disconnect the exhaust tailpipe from the outlet of the muffler and then remove the muffler. See EXHAUST SYSTEM under Engine Subsystems. 5. Disconnect the fuel line from the genset. Follow the applicable instructions depending on the fuel. |
| Engine Misfires | Faulty ignition due to: a. worn or fouled spark plugs. **b. worn breaker points. **c. incorrect ignition timing. d. faulty ignition coil, e. faulty plug wires. **f. faulty condenser. **g. faulty ignition module (electronic ignition); Lean fuel mixture due to: a. incorrectly adjusted fuel mixture screws. **b. incorrect float level. c. dirt in carburetor. d. vacuum leak.; Contaminated fuel; Carburetor icing *Gasoline sets only. | A. Replace spark plugs. b. Replace breaker points. c. Set breaker point gap. d. Test coil and replace if necessary. e. Test spark plug wires and f. Replace condenser. g. See Testing Ignition Module.; 2a. Adjust carburetor main and idle adjustment screws. b. Adjust carburetor float level. c. Disassemble carburetor and clean all internal passages. d. Locate leak and correct as required.; 3. Drain fuel tank and refill with fresh fuel. 4. In cold weather, place air preheater in winter position. |
| Engine Backfires | Faulty ignition due to: a. worn or fouled spark plugs. **b. worn breaker points. **c. incorrect ignition timing. d. faulty ignition coil, e. faulty plug wires. **f. faulty condenser. **g. faulty ignition module (electronic ignition) | A. Replace spark plugs. b. Replace breaker points. c. Set breaker point gap. d. Test coil and replace if necessary. e. Test spark plug wires and f. Replace condenser. g. See Testing Ignition Module. |
| Engine Lacks Power | Faulty ignition due to: **a. incorrect ignition timing. b. incorrect spark plug gap. **c. faulty condenser. | A. Adjust breaker point gap. b. Reset spark plug gap. c. Replace condenser. |
| Engine Overheats | Mechanical damage to engine *Gasoline sets only. | See Engine Block Assembly section. |
| Engine Hunts or Surges | 1. Sticking or binding governor linkage. 2. Incorrect governor adjustment 3. Faulty governor spring. 4. Incorrect fuel mixture due to: a. incorrectly adjusted fuel mixture screws, b. incorrect float level, or c. dirt in carburetor. 5. Governor mechanism worn excessively. *6. Carburetor icing. | 1. Clean and lubricate governor linkage. 2. Adjust governor speed and sensitivity. 3. Replace governor spring. 4a. Adjust carburetor main and idle adjustment screws. 4c. Disassemble carburetor and clean all internal passages. |
| High Oil Consumption | 1. Oil viscosity too light or oil is diluted. 2. Crankcase breather valve is dirty or defective. 3. Oil leaks. | 1. Drain oil and refill with correct viscosity oil. 2. Clean crankcase breather and replace if defective. 3. Locate source of leak and repair as required. |
| Low Oil Pressure | 1. Oil viscosity too light or oil is diluted. 2. Low oil level. 3. Low oil pressure switch defective. 4. Faulty oil bypass valve. | 1. Drain oil and refill with correct viscosity oil. 2. Add oil as required. 3. Replace oil pressure switch (see Engine Block Assembly section). 4. Inspect oil bypass valve and clean or replace as required (see Engine Block Assembly section.). |
| Black Exhaust Smoke | Lean fuel mixture due to: a. incorrectly adjusted fuel mixture screws. b. incorrect float level. c. dirt in carburetor. d. vacuum leak. | 3a. Adjust carburetor main and idle adjustment screws. 1b. Adjust carburetor float level. 1c. Disassemble carburetor and clean all internal passages. 1 Replace fuel filter. 4d. Repair vacuum leak. |
| White or Blue Exhaust Smoke | Rich fuel mixture due to: a. incorrect float level b. faulty carburetor float. | 1a. Adjust carburetor float level. 1b. Replace faulty carburetor float. |
| Engine surges | 1. Sticking or binding (mechanical) governor linkage. 2. Incorrect (mechanical) governor adjustment. 3. Faulty (mechanical) governor spring. 4. Incorrect fuel mixture due to: a. incorrectly adjusted fuel mixture screws.1 b. incorrect float level.1. 2 c. dirt in carburetor d. ignition misfires 5. Intermittent electrical connections. 6. Governor mechanism worn excessively. 7. Fuel supply problem caused by: a. Faulty fuel pump.2 b. Contaminated fuel supply.2 c. Vapor locking.2 d. Plugged fuel filter | 1. Clean governor linkage (remove dirt or ice buildup). Check that linkage does not touch other parts. 2. Adjust governor speed and sensitivity. 3. Replace governor spring. 4a. Adjust carburetor main and idle adjustment screws.1 4b. Adjust carburetor float level.1 4c. Disassemble carburetor and clean all internal passages.1 4d. Check connections, see Ignition section. 5. Check battery and ignition connections. 6. See Engine Block Assembly section.. 7a. Check fuel pump and replace if defective. 7b. Drain and refill fuel supply 7c. Check for cause of overheating 7d. Replace fuel filter. |
| Make sure there is ample fresh air when operating the genset in a confined area. | | Ensure adequate ventilation when operating the genset in a confined space. |
| Overheats | Restricted airflow due to: a.debris blocking air inlet or outlet. | Clear away debris. Do not use genset compartment for storage. |
| Lean fuel mixture | A.incorrectly adjusted fuel mixture screws. | Adjust carburetor main and idle adjustment screws.1 |
| Contaminated fuel supply | 2.Contaminated fuel.2 | Drain and replace fuel. |
| Governor mechanism worn excessively | 6.Governor mechanism worn excessively. | See Engine Block Assembly section. |
| Sticking or binding (mechanical) governor linkage | 1.Clean governor linkage (remove dirt or ice buildup). Check that linkage does not touch other parts. | |
| Incorrect (mechanical) governor adjustment | 2.Incorrect (mechanical) governor adjustment. | Adjust governor speed and sensitivity. |
| Faulty (mechanical) governor spring | 3.Faulty (mechanical) governor spring. | Replace governor spring. |
| Incorrect fuel mixture | 4a. Adjust carburetor main and idle adjustment screws. | Adjust carburetor main and idle adjustment screws.1 |
| Intermittent electrical connections | 5.Intermittent electrical connections. | Check battery and ignition connections. |
| Fuel supply problem caused by: a.Faulty fuel pump. | | Check fuel pump and replace if defective. |
| Fuel supply problem caused by: b.Contaminated fuel supply. | | Drain and refill fuel supply |
| Fuel supply problem caused by: c. Vapor locking. | | Check for cause of overheating |
| Fuel supply problem caused by: d.Plugged fuel filter. | | Replace fuel filter. |
| Carburetor icing | 8.Carburetor icing.2 | In cold weather, place air preheater in winter position. |
| Faulty ignition due to: a. worn or fouled spark plugs. | Misfires | Replace spark plugs. |
| Faulty ignition due to: b. faulty ignition coil. | Misfires | Test coil and replace if necessary. |
| Faulty ignition due to: c. faulty plug wires. | Misfires | Test spark plug wires and replace if faulty. |
| Lean fuel mixture due to: a. incorrectly adjusted main and idle adjustment screws. | | Adjust carburetor main and idle adjustment screws. |
| Lean fuel mixture due to: b. incorrect float level. | | Adjust carburetor float level. |
| Lean fuel mixture due to: c. dirt in carburetor. | | Disassemble carburetor and clean all internal passages. Replace fuel filter. |
| Lean fuel mixture due to: d. vacuum leak. | | Locate leak and correct as required. |
| Lean fuel mixture due to: e. altitude setting. | | Reset altitude adjust knob on carburetor. |
| Contaminated fuel. | | Drain fuel tank and refill with fresh fuel. |
| Carburetor icing. | | Place air preheater in winter position. |
| Faulty ignition due to incorrect spark plug gap. | | Reset spark plug gap. |
| Dirty air cleaner. | | Replace air cleaner. |
| Restricted fuel flow due to: a. Plugged fuel filter. | | Replace fuel filter. |
| Dizziness | | IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired. |
| Muscular Twitching | | IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired. |
| Vomiting | | IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired. |
| Weakness and Sleepiness | | IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired. |
| Inability to Think Coherently | | IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical attention. Shut down the unit and do not operate until it has been inspected and repaired. |
| The engine fails to crank. | | A. Try starting at the genset rather than at the remote control. b. Replace fuse F1 on the control panel if it has blown. c. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and the genset. d. Recharge the battery. Refer to the battery manufacturer's recommendations. |
| The engine cranks slowly. | | A. Disconnect the air conditioner and other large loads. b. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and the genset. c. Recharge the battery. Refer to the battery manufacturer's recommendations. d. Change the engine oil to oil having the proper viscosity for the ambient temperature. See Table 1. |
| The engine cranks but fails to start. | | A. Check the fuel tank and fill if necessary. b. Open any closed fuel shut off valve. c. Check engine oil level and add oil as necessary. d. Replace fuse F2 (side of control panel) if it has blown. e. Service the air cleaner. f. Secure the spark plug leads on the spark plugs. g. Replace the spark plugs. |
| The engine runs and then stops or surges. | | A. Check the fuel tank and fill if necessary. b. Check the engine oil level and add oil as necessary. Drain excess oil if the level is above the dipstick Full mark. c. Check and reset the carburetor preheater lever and altitude adjust knob. See Varying Weather and Altitude. d. Secure the spark plug leads on the spark plugs. e. Replace the spark plugs. |
| There is no electrical power even though the genset runs. | | A. Reset tripped circuit breakers. See Powering Equipment. b. Unless there is an automatic power transfer switch, plug the boat power cord into the genset power output receptacle (if so equipped) or turn the pontoon boat power selector switch to its genset position (if so equipped). |
| The remote battery condition meter indicates low voltage. | | A. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and the genset. b. Recharge the battery. Refer to the battery manufacturer's recommendations. |
| The genset keeps stalling or the circuit breaker keeps tripping. | | Try running with fewer appliances connected. See Powering Equipment. |
| Black smoke exits the tailpipe. | | Service the air cleaner. |
| FAILS TO CRANK | 1. Low battery. 2. Bad battery connection. 3. Blown fuse. | 1. Check battery electrolyte level. 2. Clean and tighten all battery and cable connections. 3. Replace fuse on control box. See specifications for proper fuse rating. |
| CRANKS SLOWLY | 1. Low battery. 2. Bad battery connection. 3. Oil is too heavy. 4. Load connected. | 1. Check battery electrolyte level. 2. Clean and tighten all battery and cable connections. 3. Replace with lighter oil. 4. Remove load. |
| CRANKS BUT WON’T START | 1. Fuel below genset pick-up level 2. Fuel supply shutoff valve closed. 3. Carbon deposits on spark plugs. 4. Blown fuel pump/in tank. | 1. Add fuel. 2. Fully open fuel supply valve. 3. Remove spark plugs and clean. 4. Replace fuse with same type and rating. If problem persists, see Onan service center. |
| EXHAUSTING BLACK SMOKE | 1. Rich fuel mixture. 2. Dirty air filter. 3. Choke stuck. | 1. Turn main fuel adjustment in 1/8 turn (location of adjustment is shown in Figure 3-1). 2. Replace air filter. 3. Contact an Onan service center. |
| UNIT RUNS THEN STOPS | 1. Out of fuel. 2. Low oil level. 3. Excess oil. | 1. Refill fuel tank. 2. Add oil if necessary. 3. Reduce engine oil level. |
| UNIT RUNS BUT SURGES | 1. Loose or worn spark plug leads at spark plugs and ignition coil. 2. Ignition coil, wiring, or control components defective. 3. Faulty spark plugs. 4. Governor out of adjustment. | 1. Check security of spark plug leads at spark plugs and ignition coil. Replace leads if worn. 2. Contact an Onan representative. 3. Remove and clean or replace faulty spark plugs. 4. Contact an Onan service center. |
| Low Bat LED (red) MAY flash ON | | If it stays on during operation, see BATTERY CARE under Periodic Maintenance. |
| Engine does not crank or start after several tries or stops running. | | See Troubleshooting if the engine does not crank or start after several tries or stops running. |
| The engine fails to crank at the remote START switch. | | A. Turn the enable switch (if so equipped) to the enable position. b. Try starting at the genset rather than at the remote control. c. Push the genset control panel switch to RESET and then to START. |
| The engine fails to crank at the genset START switch and Start Sol (Fig. 3) does not light. | | A. Turn the enable switch (if so equipped) to the enable position. b. Push the genset control panel switch to RESET and then to START. c. Replace fuse F1 on the side of the control box if it has blown. d. Clean and tighten the positive (+) and negative (- ) battery cable connections at the battery and the genset. e. Recharge the battery. Refer to the battery manufacturer’s recommendations. |
| The engine fails to crank at the genset START switch but Start Sol (Fig. 3) does light. | | A. Clean and tighten the positive (+) and negative (- ) battery cable connections at the battery and the genset. b. Recharge the battery. Refer to the battery manufacturer’s recommendations. |
| The engine cranks but fails to start. Fuel Pump, AVR Field and Ignition (Fig. 3) do light. | | A. Check the fuel tank and fill if necessary. b. Open any closed fuel shut off valve. c. Check engine oil level and add oil as necessary. d. Service the air cleaner. e. Secure the spark plug leads on the spark plugs. f. Replace the spark plugs. |
| The engine cranks but fails to start. Fuel Pump, AVR Field or Ignition (Fig. 3) does not light. | | Contact an authorized Onan dealer. |
| There is no electrical power even though the genset runs and Gen AC (Fig. 3) lights. | | A. Reset tripped circuit breakers. See Powering Equipment. b. Unless there is an automatic power transfer switch, plug the vehicle power cord into the genset power output receptacle (if so equipped) or turn the vehicle power selector switch to its genset position (if so equipped). |
| Low Bat (Fig. 3) lights and/or the remote battery meter (Fig. 4) indicates low voltage. | | A. Clean and tighten the positive (+) and negative (- ) battery cable connections at the battery and the genset. b. Recharge the battery. Refer to the battery manufacturer’s recommendations. |
| Eng Cranks But Will Not Start (Genset) | | -01 Check: - Spark plugs - Ignition coil - Ignition module -02 Perform checks in step 01 |
| Engine Overfueling (Genset) | | -01 Check: - Spark plugs - Fuel pressure at carburetor - Vacuum pull−off - Electric choke heater -02 Perform checks in step 01 - Check: - Governor adjustments - Carburetor adjustments -03 Perform checks in step 02 - Check: - Ignition coil - Ignition module |
| Engine Unstable (Hunts) (Genset) | | -01 Check: - Fuel supply - Fuel Lines for leakage - Loose wire connection -02 Perform checks in step 01 - Check: - Governor linkage for binding - Governor adjustments - Carburetor adjustments |
| Engine Will Not Crank (Genset) | | -01 Check: - Low battery voltage - Terminal connection−loose or dirty - Battery cable size - Starter drive engagement -02 Perform checks in step 01 - Check: - Remote control - Connections on PCB control board - Start solenoid - Starter |
| High/Low AC Output (Genset) | | -01 Check: - Broken or loose wires - Voltage regulator - Transformer regulator - Engine speed - Voltage ad |
| Smoke and rough operation | Oil in the cylinders has not been burned off yet. | Continue running the generator set until the oil in the cylinders is burned. |
| Generator set runs louder than usual, compartment has holes to the interior, or exhaust system has leaks | | Do not operate the generator set and have the exhaust system repaired as soon as possible. See your Onan service center. |
| Loose or Corroded Battery Connection | | Make sure the battery cable connections are clean and tight. Use a terminal puller when removing cables for any reason. |
| NO AC OUTPUT | . Blow fuse or circuit breaker (if used). Then replace fuse or reset circuit breaker. . Disconnected wire or lead on brushes. . Brushes not making contact with slip rings may be excessively worn. | . Look for cause and repair. |
| LOW AC OUTPUT | . External short circuit on line. Circuit problem. . Generator overloaded. . Remove part of load. . Shorted or grounded circuit in field or armature winding. | . Test for open, grounded, or shorted windings. Repair or replace as necessary. . Engine not running properly causing generator to slow down. |
| NOISY GENERATOR | . Defective bearing in end bell. . Brush rig loose. . Armature and field frame rubbing together. | . Replace bearing. . Retorque. . Check for generator misalignment and for varnish lumps between armature and field. Repair as necessary. . Turn commutator on lathe; undercut mica insulation. |
| GENERATOR OVERHEATS | . Windings and parts covered with oil or dirt. | . Clean generator. . Take necessary steps to allow for proper cooling. |
| Air intake restricted or incoming air too hot. | | . Take necessary steps to allow for proper cooling. |