. MicroLite 4000 Series. Table of Contents SECTION TITLE PAGE SAFETY PRECAUTIONS.

1. Onan 4000 Micro Quiet Generator Carburetor
2. Onan 4000 Microquiet Generator Service Manual
3. Onan Microquiet 4000 Generator Owners Manual

GENERATOR. Generator Description. Safety Precautions Thoroughly read the SERVICE MANUAL before servic- The genset must not be connected to the public utility ing the genset. Reliable service can be obtained only or any other source of electrical power. Connection with close adherance to the procedures in this manu- could lead to electrocution of utility workers, damage to equipment and fire. Redistribution or publication of this document, by any means, is strictly prohibited.

SN5304U1G2RA 304 cc placement parts are recommended for best results. When contacting Onan for parts, service or product information, be ready to provide the model number and the serial number, both of which appear on the genset nameplate (Figure 1-1). Each character of FIGURE 1-1. Model Number Identification Serial Number Identification Figure 1-2 shows a breakdown of the model num- Figure 1-3 shows a breakdown of the serial number ber for a typical genset.

For a typical genset. SERIAL MODEL 1. Power capacity in kilowatts - (4000 watts) 1. Specifications GASOLINE MODELS LPG MODELS 4.0 KY 3.6 KY 3.6 KY 3.3 KY GENERATOR: 2-Pole Revolving Field, Self-Excited, Electronically Regulated, 1-Phase Power 4000 watts 3600 watts 3600 watts 3300 watts Frequency 60 Hertz 50 Hertz 60 Hertz 50 Hertz Voltage 100/120 volts 100/220/230 volts.

Redistribution or publication of this document, by any means, is strictly prohibited. Dimensions and Clearances All clearances are at 70 F (21 C) room temperature. All measurements are listed in inches with millimeter measurements in parentheses.

Measurements are for standard size parts. FACTORY SPECIFICATION ALLOWABLE DESCRIPTION MIN.

LIMIT Cylinder Head Cylinder Head Distortion –. All clearances are at 70 F (21 C) room temperature. All measurements are listed in inches with millimeter measurements in parentheses. Measurements are for standard size parts. FACTORY SPECIFICATION ALLOWABLE DESCRIPTION MIN. LIMIT Piston Pin Piston Pin O.D. 0.7087 0.7089 0.7067 (Between Pin Bosses).

All clearances are at 70 F (21 C) room temperature. All measurements are listed in inches with millimeter measurements in parentheses. Measurements are for standard size parts. FACTORY SPECIFICATION ALLOWABLE DESCRIPTION MIN.

LIMIT Intake Valve Seat Seat Width 0.0433 (1.1) Seat Angle Exhaust Valve. Redistribution or publication of this document, by any means, is strictly prohibited. Torque Specifications Mounting screws and nuts must be tightened to the specified torque settings listed in the following tables. All threads must be clean and lubricated with new engine oil before tightening. The cylinder head mounting bolts must be tightened in the proper sequence, refer to Section 10. Engine Block Assembl y. When tightening torques are not specified, tighten the screws and nuts according to Tables 4-3 and 4-4 on Page 4-2.

GENERATOR TORQUE SPECIFICATIONS ITEM POUND - FEET NEWTON - METERS Rotor Through-Bolt 40-50 54-68 Stator Through-bolt 7-11 Endbell to Stator Housing 7-11 Mount Assy. Bolt (Spec A) 38-43 52-58 Mount Assy. Bolt (Begin Spec B) 35-40 47-53 Stator Housing to Engine Block 15-18 21-24. The following special tools are required to service ing safeguards.

See the Onan Tool Catalog. Safeguards to Avoid Hazards Engine Tools Use personal protection: Protect your body. HAZARDS AND THEIR SOURCES Fire and explosions Electrical shock (AC) Leaking or spilled fuel Improper genset load connections Hydrogen gas from charging battery Faulty RV wiring Oily rags improperly stored Faulty electrical appliance Flammable liquids improperly stored Faulty genset wiring Any fire, flame, spark, pilot light, arc- Working in damp conditions producing equipment or other ignition. M1723-1s FIGURE 5-1. TYPICAL COMPARTMENT MOUNT INSTALLATION (SPEC A SHOWN) M2001s FIGURE 5-2.

TYPICAL UNDER-FLOOR MOUNT INSTALLATION (BEGIN SPEC B SHOWN) Redistribution or publication of this document, by any means, is strictly prohibited. Disconnecting Set from Vehicle Systems plug the end of the fuel line to prevent leak- age or an accumulation of explosive gaso- Disconnect the following items from the genset.

Re- line vapor. Fer to Figures 5-1 and 5-2 on Page 5-3 for compo- B. Set Removal Park the vehicle on a level surface which can sup- port the forklift. Move the transmission to PARK, After the genset is disconnected from electrical, ex- lock the brakes and remove the ignition key.

Do not haust and fuel systems, examine the set mounting move the vehicle during this procedure. Under-Floor Mount: 4. Loosen bolts securing the side panels to the rear panel (note slotted holes) or braces and pull side panels away from genset. Use a forklift to support the genset at the points side panels to back panel bolts.

Shown in Figure 5-3. Troubleshooting INTRODUCTION the location of the test or adjustment procedure in this manual. Use the following troubleshooting guide to help Refer to Figures 6-1 and 6-2 on Pages 6-2 and diagnose genset problems. The troubleshooting 6-3 to identify the component locations for the section is divided into four parts: Spec A and Spec B models. ES2017s FIGURE 6-1. COMPONENT LOCATIONS – GASOLINE-FUELED SPEC A MODELS Redistribution or publication of this document, by any means, is strictly prohibited.

ES2017s FIGURE 6-2. COMPONENT LOCATIONS – GASOLINE-FUELED MODELS, BEGINNING WITH SPEC B Redistribution or publication of this document, by any means, is strictly prohibited. Spec A Start - Cranking Mode Battery positive (B+) is supplied to the control assembly (A1) through control fuse (F1). Holding the Start/Stop switch (S1) in the Start position activates control assembly (A1) by closing the start signal input circuit. While the Start/Stop switch is held, the control assembly supplies the following outputs: Battery positive (B+) is supplied to the start relay coil (K1). Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. SPEC A CONTROL TROUBLESHOOTING – CRANKING MODE Trouble Possible Cause Corrective Action. Spec A Start - Ignition Mode Holding the Start/Stop switch (S1) in the Start position activates the following ignition circuit: Control assembly (A1) enables the ignition circuit to open a ground path through the control assembly to the magneto assembly (G2) so that output from the magneto will energize the ignition coil (T1). With the engine cranking, a permanent magnet in the flywheel rotates, at the proper time, past the magneto to induce a voltage at the ignition coil (T1) that fires the spark plug (E1) for ignition.

Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. SPEC A CONTROL TROUBLESHOOTING – IGNITION MODE Trouble Possible Cause Corrective Action. Spec A Start - Field Flash Mode Holding the Start/Stop switch (S1) in the Start position activates the following field flash circuit: Battery positive (B+) is supplied to the control assembly (A1) and the voltage regulator (VR1) at pin 7. From pins 9 and 10 of the voltage regulator, excitation voltage is sensed through the brushes to the rotor field winding. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. SPEC A CONTROL TROUBLESHOOTING – FIELD FLASH MODE Trouble Possible Cause Corrective Action. Spec A Run Mode When the engine starts, release the Start/Stop switch and it will return to the center Run position. The following events occur: Control assembly (A1) opens the circuit to the start solenoid (K1), which opens the circuit to the starter motor (M1) to stop cranking. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii.

SPEC A CONTROL TROUBLESHOOTING – RUN MODE Trouble Possible Cause Corrective Action. Spec A Battery Charge Mode With the genset running, AC voltage is produced in the B1-B2 windings for the battery charge circuit. The AC output voltage from the B1-B2 winding is converted to DC voltage when it passes through the full-wave rectifier bridge (CR1). Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. SPEC A CONTROL TROUBLESHOOTING – BATTERY CHARGE MODE Trouble Possible Cause Corrective Action. Spec A Stop Mode Momentarily pushing the Start/Stop switch (S1) to the Stop position begins the stop mode with the following results: Control assembly (A1) de-energizes the ignition enable circuit, grounding the magneto (G2) ignition circuit to stop the engine.

Control assembly (A1) also opens the circuit to the fuel pump (E2) and to the remote control. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. SPEC A CONTROL TROUBLESHOOTING – STOP MODE Trouble Possible Cause Corrective Action. Begin Spec B Start - Cranking Mode Battery positive (B+) is supplied to the control assembly (A1) through control fuse (F1). Holding the Start/Stop switch (S1) in the Start position activates control assembly (A1) by closing the start signal input circuit.

While the Start/Stop switch is held, the control assembly supplies the following outputs: Battery positive (B+) is supplied to the start relay coil (K1). Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. BEGIN SPEC B CONTROL TROUBLESHOOTING – CRANKING MODE Trouble Possible Cause Corrective Action. Begin Spec B Start - Ignition Mode Holding the Start/Stop switch (S1) in the Start position activates the following ignition circuit: Control assembly (A1) enables the ignition circuit to open a ground path through the control assembly to the magneto assembly (G2) so that output from the magneto will energize the ignition coil (T1). With the engine cranking, a permanent magnet in the flywheel rotates, at the proper time, past the magneto to induce a voltage at the ignition coil (T1) that fires the spark plug (E1) for ignition.

Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. BEGIN SPEC B CONTROL TROUBLESHOOTING – IGNITION MODE Trouble Possible Cause Corrective Action. Begin Spec B Start - Field Flash Mode Holding the Start/Stop switch (S1) in the Start position activates the following field flash circuit: Battery positive (B+) is supplied to the control assembly (A1) and the voltage regulator (VR1) at pin 7. From pins 9 and 10 of the voltage regulator, excitation voltage is sensed through the brushes at the rotor field winding. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. BEGIN SPEC B CONTROL TROUBLESHOOTING – FIELD FLASH MODE Trouble Possible Cause Corrective Action. Begin Spec B Run Mode When the engine starts, release the Start/Stop switch and it will return to the center Run position.

The following events occur: Control assembly (A1) opens the circuit to the start solenoid (K1), which opens the circuit to the starter motor (M1) to stop cranking. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. BEGIN SPEC B CONTROL TROUBLESHOOTING – RUN MODE Trouble Possible Cause Corrective Action.

Begin Spec B Battery Charge Mode – 50 Hz Only With the genset running, AC voltage is produced in the B1-B2 windings for the battery charge circuit in the 50 Hz mod- els only. The 60 Hz Spec B models do not have battery charging. The AC output voltage from the B1-B2 winding is converted to DC voltage when it passes through the battery charger assembly (VR2). Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures.

Review safety precautions on page iii. BEGIN SPEC B CONTROL TROUBLESHOOTING – BATTERY CHARGE MODE Trouble Possible Cause Corrective Action. Begin Spec B Stop Mode Momentarily pushing the Start/Stop switch (S1) to the Stop position begins the stop mode with the following results: Control assembly (A1) de-energizes the ignition enable circuit, grounding the magneto (G2) ignition circuit to stop the engine. Control assembly (A1) also opens the circuit to the fuel pump (E2), the fuel shutoff solenoid (E3), and to the remote control. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii.

BEGIN SPEC B CONTROL TROUBLESHOOTING – STOP MODE Trouble Possible Cause Corrective Action. GENERATOR TROUBLESHOOTING and 6-2 on pages 6-2 and 6-3 show the location of the generator components. Refer to the wiring diagrams in Section 12. Wiring Schematic/Diagram Use the following troubleshooting guide to help lo- cate problems related to the generator. Figures 6-1 for wiring connections.

Spec A Generator AC Output Mode When the engine starts and begins to come up to speed, AC voltage is produced in the battery charge winding B1-B2, the quadrature winding Q1-Q2 and in the AC windings T1-T2. These outputs perform the following functions: The battery charge winding B1-B2 is used to power the control assembly (A1), fuel pump (E2), the remote con- trol, and to prevent discharge of the genset starting battery during genset operation. Spec B Generator AC Output Mode When the engine starts and begins to come up to speed, AC voltage is produced in the battery charge winding B1-B2 (50 Hz only), the quadrature winding Q1-Q2 and in the AC windings T1-T2 (T3-T4 50 HZ). These outputs perform as follows: The battery charge winding B1-B2 is provided on the 50 Hz models only to power battery charger (VR2).

Many troubleshooting procedures present hazards which can result in severe personal WARNING injury or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery hazards should perform service procedures. Review safety precautions on page iii.

GENERATOR TROUBLESHOOTING Trouble Possible Cause Corrective Action. ENGINE PRIMARY SYSTEMS Poor engine performance is often caused by a dirty carburetor. Make certain that the carburetor is TROUBLESHOOTING clean before troubleshooting for performance prob- Use the following troubleshooting guide to locate lems.

Problems with the engine primary systems. Many of the primary systems can be serviced without re- moving the genset from the vehicle. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death.

Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. TROUBLESHOOTING ENGINE PRIMARY SYSTEMS Trouble Possible Cause Corrective Action. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. TROUBLESHOOTING ENGINE PRIMARY SYSTEMS Trouble Possible Cause Corrective Action.

Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii.

TROUBLESHOOTING ENGINE PRIMARY SYSTEMS Trouble Possible Cause Corrective Action. Many troubleshooting procedures present hazards that can result in severe personal inju- WARNING ry or death. Only qualified service personnel with knowledge of fuels, electricity, and machinery haz- ards should perform service procedures. Review safety precautions on page iii. TROUBLESHOOTING ENGINE PRIMARY SYSTEMS Trouble Possible Cause Corrective Action. Control INTRODUCTION Control Assembly (A1) Optional Remote Start/Stop Control (A2, A3) This section covers control operation, component Battery Charge Resistor (R1) locations, basic troubleshooting and test proce- dures.

The control consists of the circuitry used for Rectifier Bridge (CR1) starting, monitoring fault conditions, instrumenta- Battery Charger Assembly (VR2) tion, battery charging, and stopping. Start Solenoid (K1) panel. If an overload occurs, the breaker can be re- set after all loads are removed from the genset. The start solenoid (K1) is used for closing and open- Control Assembly (A1) ing the circuit between the battery and the starter motor. Optional Remote Control (A2, A3) CONTROL OPERATION The schematic diagrams in Section 12. Wiring The remote control is an optional accessory that al- Schematic/Diagram can be used to help follow the lows the genset to be started, monitored, and circuit description. Always refer to the specific wir- stopped from a remote location.

Run Mode A low oil level will cause the low oil level switch (S2) to close. This closes a ground path to the magneto When the engine starts, release the Start/Stop assembly (G2) eliminating ignition spark and pre- switch and it will return to the center Run position. Venting the engine from operating. CONTROL COMPONENT TESTS Start/Stop Switch (S1) Disconnect the P1 (or J1 for Spec B) connector from The following control component checks can be control assembly (A1). See Figure 7-3.

Continuity should be measured between pin 1 and pin 3 (pin 13 made to verify if components are defective. Start Solenoid (K1) Electrical shock can cause severe WARNING personal injury or death. Do not touch the volt- meter or any wiring when the genset is operat- A check can be made by measuring the resistance ing.

Attach and remove meter leads only when of the coil terminals I and S (Figure 7-4). SPEC A CONTROL OUTPUTS CONTROL OUTPUT CONTROL MODE (CONNECTOR PIN) CRANK STOP TABLE 7-2. BEGIN SPEC B CONTROL OUTPUTS CONTROL OUTPUT CONTROL MODE (CONNECTOR PIN) CRANK STOP FIGURE 7-5. CONTROL ASSEMBLY (A1) CHECK Redistribution or publication of this document, by any means, is strictly prohibited. Resistor (R1) – Spec A Only The battery charge resistor can be checked with an ohmmeter.

Disconnect the leads from the resistor and measure the resistance between terminals on one end to the resistor and the terminals on the oth- er end. Battery Charger Assembly (VR2) – Begin Spec B, 50 Hz Only The battery charger is located on the left side of the genset housing. The battery charger can be checked with a voltmeter. A voltage measurement between the B+ terminal and ground (Figure 7-7), with the genset off should read the starting battery voltage (approximately 12 VDC).

Transformer (T1) – Begin Spec B, 50 Hz Only The transformer (see /Figure 7-8) is located on the backside of the genset (see Figure 6-2 on Page 6-3). The transformer can be checked with an ohm- meter. Isolate the transformer leads from the circuit and measure the resistance between H1 - H2 pri- mary winding. Primary Engine Systems INTRODUCTION Inspection This section describes the engine primary systems Inspect the air inlet and outlet passages. Remove service procedures.

Many of the primary systems the access panel and inspect the engine and control can be serviced without removing the genset from area. Use only Onan replace- ment parts to service the exhaust system. Un- authorized modifications will void the Onan EXHAUST SYSTEM warranty. EXS1170-5s EXS1170-7s FIGURE 8-2. COMPARTMENT MOUNT EXHAUST SYSTEM Muffler Assembly mounting hardware to the specified torque. Exhaust gas can cause severe per- WARNING Obtain the required replacement parts including a sonal injury or death.

To prevent exhaust leaks, new exhaust gasket. Install the muffler in reverse always install a new exhaust gasket, and re- order of removal. Begin Spec B: Use 1-1/4 inch O.D. (1-1/8 inch I.D.) proach or departure angle unless it is adequate- 18-gauge aluminized steel or stainless steel tubing ly protected. Use only Onan-specified exhaust for tailpipe.

Equipment with the genset. Use a sufficient. Do not terminate the exhaust tailpipe under the fuel Excessive exhaust back pressure CAUTION tank fill spout to prevent spilled fuel from being ig- can cause engine damage. If tailpipe deflector is nited by a hot tailpipe.

Used, make sure it is large enough to prevent back pressure. IGNITION SYSTEM If the spark plug is in good condition, proceed to the Ignition Coil section, following. The ignition system consists of the magneto as- Ignition Coil (T1) sembly, ignition coil, spark plug and ignition wiring. If a problem with the ignition system is suspected, The ignition coil is a transformer that steps up the the spark plug can be inspected and an ignition magneto output voltage to about 20,000 volts for. Ignition Coil Ohmmeter Check: Remove the con- One wire from the magneto to the ignition coil trol panel mounting screw (Torx T-30) to access the primary. Ignition coil.

Check the ground lead for continuity One ignition enable wire from the control as- between the ground lead terminal and a clean sembly to the magneto. Magneto Assembly (G2) burned in the combustion chamber.

A stuck or dam- aged breather valve can cause oil leaks, high oil The magneto assembly is a noncontact capacitive consumption, rough idle, reduced engine power, discharge (breakerless) type that is mounted to the and a rapid formation of sludge and varnish within generator endbell. GOVERNOR tempting to adjust the governor (see the Gasoline Fuel System section on Page 8-11). The governor controls engine speed, which directly A binding governor shaft, governor linkage, or car- affects the frequency and voltage output of the gen- buretor throttle will cause hunting. Also a fouled erator.

ence between no-load and full-load) without TABLE 8-1 CHECKING VOLTAGE AND SPEED/FREQUENCY causing a hunting condition. To increase the sensitivity, turn the adjustment screw counter- clockwise. To decrease the sensitivity, turn the adjustment screw clockwise.

60 Hz 50 Hz 50 Hz 6. GASOLINE FUEL SYSTEM The fuel system must be properly adjusted and in good condition for efficient genset operation. The main components of the fuel system include: Air filter Air preheater Choke Carburetor Intake manifold Fuel filter Fuel pump Air Filter and Preheater Assembly FS1866s This assembly consists of the air filter housing, air filter, and preheat door assembly. Carburetor and Intake Manifold Assembly 3. Remove the carburetor mounting screws from the left side of the endbell.

This assembly consists of the carburetor and the in- 4. Close the choke and throttle plates by rotating take manifold assembly. See Figure 8-9. It is easier their shafts in a counterclockwise direction. Carburetor Replacement (Beginning Spec D) Other than turning the altitude adjust knob shown in Figure 8-10 (which changes the main fuel mixture within a limited range), fuel mixture adjustments should not be attempted. Nor should the carburetor be overhauled.

Instead, a malfunctioning carbure- tor should be replaced. Carburetor Mixture Screw Adjustments 3. Turn the main adjustment screw inward until voltage or frequency drop and then outward (Does Not Apply to Spec D and Later) until voltage or frequency drop again. Locate The most common causes of poor carburetion are the point where voltage and frequency are the the idle and main mixture screws being out of ad- highest. Remove the float chamber and gasket by re- FIGURE 8-12. CARBURETOR OVERHAUL moving the chamber set plug. (PRIOR TO SPEC D) Redistribution or publication of this document, OnaFresh is a trademark of Onan Corporation.

By any means, is strictly prohibited. Cleaning and Repair Procedure: Forcing the mixture adjustment CAUTION screws tight will damage the needle and 1. Soak all metal components to be reused in car- seat. Turn them in until only light tension buretor cleaner. Do not soak rubber or plastic can be felt.

Choke Assembly The choke housing becomes very WARNING hot during operation and can cause severe The genset has an automatic choke assembly that burns if touched. Allow the genset to cool down consists of a bimetal choke coil, coil housing, heater before handling the choke assembly. SIGHT WINDOW CHOKE LINKAGE FS1867s FIGURE 8-15. CHOKE ASSEMBLY Bimetal Coil Replacement: After making the the adjustment plate to release the bimetal coil. Choke adjustment, start the genset and observe en- 3. Remove choke linkage from the bimetal coil gine operation. If the choke does not open properly, and install linkage on the new coil.

Do not substitute an automotive WARNING electric fuel pump for the Onan-supplied fuel pump. The output pressure from an automotive FS1868-1s pump is much higher and can cause carburetor flooding or fuel leakage, creating a fire hazard. (Figure 8-17). The pump will not place fuel pump with an Onan-supplied pump. Work properly if the cranking or running voltage is less than 6 VDC. FS1868s FIGURE 8-17. FUEL PUMP TEST Redistribution or publication of this document, by any means, is strictly prohibited.

LPG FUEL SYSTEM See the instructions on how to remove and replace the carburetor under the subheadings Air Filter and LPG is flammable and explosive WARNING Preheater Assembly on Page 8-11 and Carburetor and can cause asphyxiation. NFPA 58, Section and Intake Manifold Assembly on Page 8-12. Checking and Adjusting Regulator Lock-off the adjusting screw locknut and test lock- Pressure: Lock-off pressure is determined as fol- off pressure again. Repeat the procedure lows by pressurizing the back (vent) side of the reg- if necessary.

Ulator diaphragm to simulate carburetor venturi If the lock-off pressure is less than 0.10 vacuum: inches WC (2.5 mm WC), loosen the lock. Fuel-Shutoff Solenoid Valve Leak Test: See Figure 8-20. If there is a smell of gas when the genset is not running, or any other reason to suspect that the valve is leaking, connect the inlet of the valve to a source of air pressure regu- lated to not more than 14 inches WC (356 mm WC) and disconnect the outlet hose.

LPG Carburetor (Prior to Spec E) tor is resting against the throttle stop screw. Ad- just the stop screw to obtain a setting of 55 ' See Figure 8-22. LPG carburetors prior to Spec E 1 Hz (45 ' 1 Hz on 50 Hz units). Have two adjustment screws that must be properly 6. ELECTRIC STARTER section.

If low or no voltage is measured check the starting battery, start solenoid, and control A 12-volt electric starter with a negative ground is wiring. Used for cranking the genset. When the starter is energized, an inertial engagement system causes the starter pinion gear to engage the ring gear on the fan hub assembly. Starter Disassembly Remove the engine bracket behind the starter from the engine (Torx T-30) and muffler. The genset must be removed from the vehicle be- 4. Remove the starter mounting nuts (bolts on fore the starter can be serviced.

Onan 4000 Micro Quiet Generator Carburetor

See Section 5. Pre- Spec A). Testing Armature for Grounds Touch one ohmmeter lead to a commutator bar, touch the other lead to the armature shaft and the core laminations.

A low resistance reading indi- cates a grounded armature. Replace a grounded armature with a new one. See Figure 8-25. Testing Armature for Shorts Use a growler (Figure 8-26) to locate shorts in the armature. Starter Re-assembly 4. Insert the brush springs into brush holders.

In- sert the brush tabs into the spring ends and Use this procedure to return the electric starter as- slide brushes into brush holders in endcap. Sembly to service.

Make sure all brush wires are facing up. Place a spring washer and a flat washer on the B. With the chamfered side of the shaft hole shaft, as shown in Figure 8-29. Facing up, place a plastic retainer on the shaft and line up the hole with a hole in the 2. Carefully mount the starter on the endbell and 3. Connect the positive (+) cable to the starter ter- tighten the mounting bolts to 30-33 lb-ft (41-45 minal.

Mount the housing on the genset and install the genset into the vehicle. Redistribution or publication of this document, by any means, is strictly prohibited.

Generator GENERATOR DESCRIPTION Generator Cooling Cooling air for the generator is provided by a centrif- The KY genset uses a 2-pole, revolving field, gener- ugal fan mounted on the rotor shaft next to the bear- ator design. Output voltage is controlled by an elec- ing. GENERATOR OPERATION 9-3 and Figure 9-2 on Page 9-4 to identify the var- ious generator components described in each sec- Refer to the schematic in Section 12. Wiring Sche- tion. Raising the generator and engine assembly matic/Diagram that corresponds to your genset to above the base assembly is necessary to disas- semble the generator. G1247s FIGURE 9-1. SPEC A GENERATOR COMPONENTS Redistribution or publication of this document, by any means, is strictly prohibited.

G1247s FIGURE 9-2. BEGIN SPEC B GENERATOR COMPONENTS Redistribution or publication of this document, by any means, is strictly prohibited.

Connect a lifting hoist to the lifting eye on the 8. Remove the air housing assembly from the top of the endbell and slowly raise the genera- endbell (Figure 9-2 on Page 9-4). Tor end of the genset so the bottom of the end- Spec A and Begin Spec B: bell is higher than the side of the base assem- bly.

Prepare the brushes for endbell removal. Remove the stator mounting screws. Carefully disconnect the wire harness leads Carefully pull the stator straight out from the from the brush block and pull each brush out- housing. If the stator will not slide out, tap on ward from the holder and at the same time in- generator housing while pulling on the stator to sert a piece of wire into the small hole in the. Generator Assembly 6. Install the fan hub assembly onto the rotor shaft and align the key slot on the fan hub with the Use the following procedures to assemble the gen- key slot in the rotor shaft. Install the key into the erator: key slot.

GENERATOR TESTING voltage regulator for field flashing and voltage build- This section covers test procedures for the rotor Electrical shock can cause severe WARNING and stator windings. Begin with the Field Voltage personal injury or death. Use extreme caution Test, following, to help locate possible problems. When working on electrical circuitry. Test A: Connect a DC voltmeter into the back side and Figure 9-8 on Page 9-10 show the rotor re- of the voltage regulator connector J4 as follows: At- moved from the genset for testing.

The rotor can be tach the positive (+) meter lead to J4 pin 7 and the tested without removing it from the generator. Open or Shorted Test: To test for open windings, set the ohmmeter on the highest resistance scale. Place the test prods on the slip rings as shown in Figure 9-8. The ohmmeter should indicate continu- ity between the slip rings of approximately 19 to 27 ohms. STATOR GROUND TEST test prods to the terminals specified in Table 9-2. A reading of less than the value shown in Table 9-2 at TEST POINT OHMMETER READING 77 F (25 C) indicates a shorted winding.

If stator tests indicate a shorted winding, replace the stator. VOLTAGE REGULATOR (VR1) TEST the painted part of the wire is not visible, the brush is excessively worn and must be replaced.

Always re- Confirm that the voltage regulator is faulty before place the brush springs when installing new replacing it. Use a meter with a diode checking func- brushes to maintain proper tension on the brushes.

Place the rotor in the machine lathe and center. Turn the rotor and use a commutator stone (Onan tool #420–0259) against the rotating slip rings to clean and true the slip rings. Turn the rotor until all grooves or roughness are smoothed out. Use a small puller with grips that will fit between the bearing and the collector ring assembly (Figure 9-13) or use an arbor press to remove the bearing. Cover the end of the rotor shaft with a steel plate to prevent deformation of the shaft during removal.

Engine Block Assembly INTRODUCTION B. Feeling compression air escaping the spark plug hole.

This section covers service procedures for the en- C. Using a tester with a T.D.C. Indicator fea- gine block assembly. A leak down test can be per- ture. TABLE 10-1. LEAK DOWN CHECK POINTS AIR LEAKAGE AT: PROBABLE CAUSE OIL PAN AND OIL LEVEL SWITCH Remove the oil plug and drain the crankcase oil.

OIL PAN REMOVAL (SPEC A Remove the oil pan mounting bolts and pan (Figure SHOWN) 10-2). ROCKER ARMS, PUSH RODS AND CYLINDER HEAD Remove the cylinder head for cleaning when poor engine performance is noticed or to inspect the valves. Remove the rocker arm mounting nuts.

Re- move the rocker arms and push rods (Figure 10-4). VT1037-2s FIGURE 10-6.

OVERHEAD VALVE SYSTEM VALVE SYSTEM carbon particles on the seat. It may also be due to weak valve springs, insufficient tappet clearance, This engine uses an overhead valve design, as warping, and misalignment. Shown in Figure 10-6. A properly functioning valve system is essential for good engine performance.

Too much clearance in the intake guide admits air and oil into the combustion chamber, affecting car- buretion, increasing oil consumption, and making heavy carbon deposits. Clean metal is a good heat conductor but carbon insulates and retains the heat. This increases combustion chamber temper- ature which causes warping and burning.

Valve Seat Surface Width 7. Use a grinding compound to finish the seat sur- face. Clean the valve seat surface. Valve stem guides or valve seats that are worn, 2. Use a vernier caliper to measure the valve seat loose, cracked, or severely pitted should be re- width (Figure 10-10).

Valve Clearance Adjustment The valve clearance can be checked and adjusted. Adjust the valve clearance only when the engine is at ambient temperature. Follow head cover removal instructions in the Head Cover section on Page 10-2. Inspect the valve stems for proper alignment with the rocker arms. CRANKCASE COVER 1.

The crankcase cover is located in two places with dowel pins (Figure 10-13). Do not attempt to pry the crankcase cover off or damage can result. Remove the crankcase cover mounting bolts.

Hold the crankcase cover and lightly tap the end of the crankshaft with a plastic ham- mer. CAMSHAFT, TAPPET AND BALANCER REMOVAL 1. Place the engine cylinder down on a clean flat surface (Figure 10-15). Carefully pull out the camshaft assembly. Remove the valve tappets.

Mark the tappets because tappet clearances differ and the tap- pets must be reassembled in their original posi- tions. Remove the two bolts from the connecting rod cap.

Mark direction of assembly for connecting the rod, cap, and splasher. Remove the rod cap from the rod and push the piston assembly out the top of the cylinder (Fig- ure 10-18). Inspection: When rebuilding the engine, thorough- ly inspect the block for any condition that would make it unfit for further use. This inspection must be made after all parts have been removed and the block has been thoroughly cleaned and dried. Cylinder Bore Deglazing Before installing new rings, deglaze the cylinder bore. Make sure that there are no scuff marks and no wear or out-of-round beyond the specifications.

Deglazing gives a fine finish but does not enlarge the cylinder diameter, so the original pistons with new rings can be used. Remove the piston pin retainer from each side, heat the piston to 300 F (149 C) and push the piston pin out. Remove dirt and deposits from the piston sur- faces with parts cleaning solvent. Clean the piston ring grooves with a groove cleaner (Figure 10-23) or the end of a piston ring filed to a sharp point.

Piston Skirt O.D. Measurement: 1. Measure the piston skirt O.D. With an outside micrometer (Figure 10-25). If the measurement is less than the allowable limit, replace the piston.

Piston Boss I.D.: 1. Measure the piston boss I.D. In both the vertical and horizontal direction with a cylinder gauge (Figure 10-26).

Piston Ring Thickness: 1. Measure the piston ring thickness with an out- side micrometer (see Figure 10-28). If the thickness is less than the allowable limit, replace the ring. Piston Assembly Install the rings on the piston beginning with the oil control ring. Clearance between Crank Pin and Connecting Rod Big End Bore 1. Measure the crank pin O.D. And the connecting rod big end bore with a micrometer, and calcu- late the difference (Figure 10-30).

If the clearance exceeds the allowable limits, replace them. PISTON AND CRANKSHAFT INSTALLATION Lubricate the bearings with engine oil. Slide the crankshaft into the bearing and add shim(s). Install the crankcase cover and check to see that the crankshaft turns freely. Measure the side clearance of the crankshaft as follows: Side Clearance of Crankshaft 1. Crankpin Clearance Compare the widest point of the flattened Plas- ti-gage with the graduations on the envelope to 1.

Wipe the oil off the rod cap and crankpin. Determine the crankpin clearance. Place a piece of the correct size Plasti-gage 5. BEARINGS The crankshaft bearing is pressed into the engine block and three bearings are pressed into the crankcase cover.

The bearing in the engine block can be pressed out after the oil seal is removed (fol- lowing section). The bearings in the crankcase cov- er can be pulled out using a puller. COMPRESSION RELEASE SYSTEM ENGINE START POSITION (SPEC A-D ONLY) This engine has a compression release system that decreases the amount of effort required to start the engine and reduces engine run-on when stopping (Figure 10-38).

The system works as follows: 1. Service Checklist WARNING EXHAUST GAS IS DEADLY! Exhaust gases contain carbon monoxide, an odorless and colorless gas. Carbon monoxide is poisonous and can cause unconsciousness and death. Symptoms of carbon monoxide poisoning can include: Dizziness Throbbing in Temples Nausea Muscular Twitching Headache Vomiting. If the fuel system was worked on, check that the idle cuts, cracks and abrasions and make sure it is not and main adjustment screws are adjusted as de- rubbing against anything that could cause damage. Scribed in the fuel system sections of Section 8.

Pri- mary Engine Systems before starting the genset. Wiring Schematic/Diagram DRAWING NO.

Onan 4000 Microquiet Generator Service Manual

DESCRIPTION FIG NO. 611-1194 Wiring Schematic - MicroLite, Spec A (60 Hertz).12-1 611-1194 Wiring Diagram - MicroLite, Spec A (60 Hertz). Redistribution or publication of this document, FIGURE 12-1. WIRING SCHEMATIC 611-1194 (MICROLITE, SPEC A – 60 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-2. WIRING DIAGRAM 611-1194 (MICROLITE, SPEC A – 60 HERTZ) by any means, is strictly prohibited.

Redistribution or publication of this document, FIGURE 12-3. WIRING SCHEMATIC 611-1225 (MICROLITE, SPEC B THROUGH E – 60 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-4.

WIRING DIAGRAM 612-1225 (MICROLITE, SPEC B THROUGH E – 60 HERTZ) by any means, is strictly prohibited. FIGURE 12-7 Redistribution or publication of this document, FIGURE 12-5. WIRING SCHEMATIC 611-1226 (MICROLITE, SPEC B THROUGH E – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-6. WIRING DIAGRAM 612-1226 (MICROLITE, SPEC B THROUGH E – 50 HERTZ) by any means, is strictly prohibited. FIGURE 12-7.

VOLTAGE RECONNECTION DIAGRAM 612-1226 (MICROLITE, SPEC B THROUGH E – Redistribution or publication of this document, 50 HERTZ) by any means, is strictly prohibited. FIGURE 12-10. FOR CONNECTIONS SEE FIGURE 12-10 Redistribution or publication of this document, FIGURE 12-8. WIRING SCHEMATIC 611-1245 (MICROLITE, BEGIN SPEC F – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-9.

WIRING DIAGRAM 611-1245 (MICROLITE, BEGIN SPEC F – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-10. VOLTAGE RECONNECTION DIAGRAM 612-1245 (MICROLITE, BEGIN SPEC F – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-11. WIRING SCHEMATIC 612-1246 (MICROLITE, BEGIN SPEC F – 60 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-12.

Onan Microquiet 4000 Generator Owners Manual

WIRING DIAGRAM 612-1246 (MICROLITE, BEGIN SPEC F – 60 HERTZ) by any means, is strictly prohibited. FIGURE 12-15. FOR CONNECTIONS SEE FIGURE 12-15 Redistribution or publication of this document, FIGURE 12-13.

WIRING SCHEMATIC 612-1255 (MICROLITE, BEGIN SPEC F – 60 HZ/100 V) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-14. WIRING DIAGRAM 612-1255 (MICROLITE, BEGIN SPEC F – 60 HZ/100 V) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-15.

VOLTAGE RECONNECTION DIAGRAM 612-1255 (MICROLITE, BEGIN SPEC F – 50 HZ/100 V) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-16.

WIRING SCHEMATIC 611-1264 (MICROLITE, BIGIN SPEC G – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-17. WIRING DIAGRAM 611-1264 (MICROLITE, BEGIN SPEC G – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-18. VOLTAGE RECONNECTION DIAGRAM 611-1264 (MICROLITE, BEGIN SPEC G – 50 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-19.

WIRING SCHEMATIC 611-1265 (MICROLITE, BEGIN SPEC G – 60 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, FIGURE 12-20. WIRING DIAGRAM 611-1265 (MICROLITE, BEGIN SPEC G – 60 HERTZ) by any means, is strictly prohibited. Redistribution or publication of this document, by any means, is strictly prohibited.

Cummins Power Generation 1400 73rd Avenue N.E. Minneapolis, MN 55432 763-574-5000 Fax: 763-528-7229 Redistribution or publication of this document, by any means, is strictly prohibited. Cummins and Onan are registered trademarks of Cummins Inc. I have a 2003 Coachmen Lephrechau​n. The generator hasn't been started in at least the year I have had it I have been living in a full hookup park.

I am learning all about this, some say a complete overhaul, some say a new carburetor and get the gunk out that water may have gotten in it. I have been reading all about this. It is an ONAN 4000 micro quite. Can you please tell me what pages to download and keep for fixing and future maintenanc​e as I drive cross country.I know to keep the safety pages but a lot of the 158 do not apply to my generator. They just take up data.Can you help me?.

walter sawyer Apr 29, 2018 08:53.