1. Manuals
  2. Brands
  3. Generac Power Systems Manuals
  4. Engine
  5. GN190H
  6. Service and repair manual

Generac Power Systems GN190H Service And Repair Manual

Small frame gn engine
Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual

Advertisement

Table of Contents
loading

Related Manuals for Generac Power Systems GN190H

Summary of Contents for Generac Power Systems GN190H

  • Page 2 FOREWORD This manual has been written and published by GENERAC ® POWER SYSTEMS, INC. to aid our dealers’ mechanics, company serv- ice personnel and general consumers when servicing the products described herein. It is assumed that these personnel are familiar with the servicing procedures for these products, or like or similar products, manufac- tured and marketed by GENERAC ®...

  • Page 3: Table Of Contents

    TABLE OF CONTENTS DIMENSIONS AND FEATURES ......3-7 GOVERNOR ADJUSTMENT ........19-20 Initial Adjustment..........19-20 4-CYCLE ENGINE THEORY ........8 Running Adjustment ..........20 SECTION 4: OPTIONAL IDLE CONTROL ..22-23 SECTION 1: GENERAL ........9-12 GENERAL ..............22 PURPOSE AND SCOPE OF MANUAL ........ 8 OPERATING INSTRUCTIONS..........
  • Page 4 TABLE OF CONTENTS SECTION 8: IGNITION SYSTEM ...... 30-31 SECTION 11: CRANKSHAFT AND CAMSHAFT 42-45 GENERAL ..............30 CAMSHAFT REMOVAL ..........42 MAJOR COMPONENTS ..........30 Removal of Crankcase Cover........42 IGNITION COIL ASSEMBLY..........30 Camshaft Removal ............ 42 SPARK PLUG ..............30 CRANKSHAFT REMOVAL..........

  • Page 5: Dimensions And Features

    DIMENSIONS AND FEATURES SMALL FRAME ENGINES ENGINE MODEL DESCRIPTION GN190H 60 Hz “XL” style, tapered shaft GN190H Keyed 3/4” unthreaded straight shaft GN190RV Vertical tapered shaft GN191H 60 Hz “XE” or “XL” style, no oil filter GN191H 3/4” straight shaft (SAE J609a) GN191H 3/4”...
  • Page 6 DIMENSIONS AND FEATURES PTO SIDE VIEW BOTTOM VIEW — MOUNTING HOLES...
  • Page 7 DIMENSIONS AND FEATURES FRONT VIEW...
  • Page 8 DIMENSIONS AND FEATURES STARTER SIDE VIEW PTO CRANKSHAFT OPTIONS VIEW...
  • Page 9 DIMENSIONS AND FEATURES CUTAWAY VIEWS ITEM DESCRIPTION ITEM DESCRIPTION CRANKCASE PISTON PIN CRANKCASE COVER SNAP RING CYLINDER HEAD TAPPET CRANKSHAFT PUSH ROD CAMSHAFT OIL PUMP ROCKER COVER / BREATHER CYLINDER HEAD GASKET CONNECTING ROD CRANKCASE COVER BOLT PISTON RING SET ROCKER COVER GASKET OIL PICK-UP ASSEMBLY CYLINDER HEAD BOLT...

  • Page 10: 4-Cycle Engine Theory

    4-CYCLE ENGINE THEORY If the engine is to run properly, four (4) events must occur POWER IGNITION AND in the proper sequence and at the correct time. These By the time the piston reaches TDC , combustion is already events are (a) intake, (b) compression, (c) ignition and in progress.

  • Page 11: Section 1: General

    SECTION 1: GENERAL Purpose and Scope of Manual This manual contains all information normally required to service or repair the Models GN-190, GN-191 and GN-220 horizontal shaft engines. Applicable procedures are carefully explained and illustrated. For exploded views and listings of engine parts, refer to the Owner's Manual for the specific device on which the engine is used.

  • Page 12: Engine Care

    SECTION 1: GENERAL ENGINE CARE Change oil after the first eight hours of operation on a new engine. Thereafter, change oil and filter every 50 hours of oper- RECOMMENDED FUELS: ation. Change oil every 25 hours if operating under extremely dusty or dirty conditions, or in very hot weather.
  • Page 13 SECTION 1: GENERAL 7. Replace the spark plug. Use a Champion RC12YC (or 8. Check that ignition wires are free of breaks and abrasions equivalent) spark plug. and are properly routed. a. Set spark plug gap to 0.030 inch (0.76mm). 9.

  • Page 14: Oversize Parts

    SECTION 1: GENERAL OVERSIZE PARTS GENERAL: OVERSIZE VALVES: At the time this manual was published, oversize pistons, Oversize valves are not available at this time. Valve guides rings, valves, etc., were not available. Worn or damaged cannot be rebored to an oversize dimension. If valve guides parts must be replaced.
  • Page 15 NOTES...

  • Page 16: Section 2: Air Cleaners And Carburetion

    SECTION 2: AIR CLEANERS AND CARBURETION AIR CLEANER 3. Remove the paper filter. 4. Clean the paper filter by tapping gently on a flat surface. SERVICING: If it is very dirty, replace it. The engine will not run properly and may be damaged if it 5.

  • Page 17: Air Cleaner Box Installation

    SECTION 2: AIR CLEANERS AND CARBURETION Gasoline that is left in the system for long periods can form gum or varnish deposits that will adversely affect carburetor operation. NOTE: Use of a good fuel stabilizer will minimize the BREATHER HOSE formation of gum deposits during storage.

  • Page 18: Carburetor Removal

    SECTION 2: AIR CLEANERS AND CARBURETION CARBURETOR REMOVAL: 2. Inspect the THROTTLE SHAFT (Item 15) and THROTTLE VALVE (Item 10). Replace if damaged. A choke style carburetor will already be loosened from its mount 3. Inspect the IDLE JET (Item 16). Check the passages as well following step 5 in “AIR CLEANER BOX REMOVAL”...
  • Page 19 SECTION 2: AIR CLEANERS AND CARBURETION Figure 2.7 — Exploded View of Typical Carburetor ITEM DESCRIPTION ITEM DESCRIPTION Carburetor Body Throttle Shaft Felt Washer Float Throttle Shaft Spring Float Bowl Screw Bowl Nut (Main Jet) Throttle Valve Fiber Washer Throttle Shaft Bowl Gasket Idle Jet Float Pin...

  • Page 20: Section 3: Mechanical Governor

    SECTION 3: MECHANICAL GOVERNOR GOVERNOR OPERATION 1. The governor SPRING tends to pull the LEVER and THROT- GOVERNOR TLE LINK toward the "INC. RPM" direction. GEAR ASSEMBLY 2. As engine speed increases, centripetal force acts on the FLY- GOVERNOR SPOOL WEIGHT.

  • Page 21: Installation Of Governor External Parts

    SECTION 3: MECHANICAL GOVERNOR 1. Remove the CAPSCREW from the IDLE CONTROL BRACKET. INSTALLATION: 2. Loosen the GOVERNOR LEVER CLAMP BOLT. Start the new shaft into the shaft boss by tapping lightly with a soft mallet. Add red Loctite ® to the shaft. Then, use 3.

  • Page 22: Running Adjustment

    SECTION 3: MECHANICAL GOVERNOR 3. For adjustable carburetors, turn the carburetor IDLE JET in a. CARBURETOR WITH FIXED MAIN JET: Slowly adjust the (clockwise) until it just bottoms. DO NOT FORCE. Then, back IDLE SPEED SCREW to obtain best operation and high- the IDLE JET out (counterclockwise) about 1-1/2 turns (see est rpm under load (see Figure 3.6).
  • Page 23 NOTES...

  • Page 24: Section 4: Optional Idle Control

    SECTION 4: OPTIONAL IDLE CONTROL GENERAL CIRCUIT OPERATION Some applications, such as generators, may be equipped 1. With Idle Control switch set to ON: with an automatic idle control system. This type of system a. AC power is delivered from the generator's AC power provides greatly improved fuel economy by running the windings to a circuit board, for operation of the circuit engine at high governed speed only when electrical loads are...

  • Page 25: Idle Control Adjustment

    SECTION 4: OPTIONAL IDLE CONTROL IDLE CONTROL ADJUSTMENT FINAL ADJUSTMENT: On the carburetor, turn the IDLE STOP SCREW clockwise GENERAL: (faster speed) until engine speed increases to 2,280-2,400 rpm Idle speed will be correct when (a) the idle control solenoid (38-40 Hertz) (see Figure 4.4).

  • Page 26: Section 5: Rewind Starters

    SECTION 5: REWIND STARTERS GENERAL The rewind starter used on most GN series engines is a manual starter that uses a spring to rewind the starter rope after it has been pulled. Pulling the rope winds up a clock- type spiral spring in the starter housing. When the rope is released, the spring unwinds and causes the rope to wind around the pulley.

  • Page 27: Disassembly (Old Style)

    SECTION 5: REWIND STARTERS DISASSEMBLY (OLD STYLE) 3. Install RETAINER PAWL and SCREW. Tighten the SCREW to 65-75 inch-pounds. 1. Pry up the HANDLE INSERT, to expose knot In ROPE (see Figure 5.2). 4. Wind the PULLEY counterclockwise until tight. Then, allow it to unwind until the hole in the PULLEY lines up with the 2.

  • Page 28: Section 6: Electric Starters And Batteries

    SECTION 6: ELECTRIC STARTERS AND BATTERIES INTRODUCTION STARTER MOTOR OPERATING PRINCIPLES Some GN series engine applications may be equipped with Closure of the circuit to the starter motor allows battery cur- a 12-volt DC electric cranking system. Such a system converts rent to flow through a commutator, to the loops of wire in electrical energy from a battery into mechanical energy at the the armature, and back to the battery.

  • Page 29: Testing The Starter Motor

    SECTION 6: ELECTRIC STARTERS AND BATTERIES STARTER MOTOR PERFORMANCE SPECIFICATIONS AT TORQUE SPECIFICATION 12 VOLTS DC STARTER MOTOR WIRE NUT MINIMUM MOTOR RPM = 800 84 INCH POUNDS MAXIMUM AMPS = 9 TESTING THE STARTER MOTOR If the starter does not perform satisfactorily, it should be replaced. CHECKING THE PINION: BATTERY MAINTENANCE When the starter motor is activated, the pinion gear should...
  • Page 30 SECTION 6: ELECTRIC STARTERS AND BATTERIES b. Once stabilized, draw in the final sample. 5. Check and record readings of the remaining cells in the same manner. c. Draw in only enough electrolyte to obtain a reading — do not let the hydrometer float hit the suction bulb. 6.

  • Page 31: Section 7: Covers And Shrouds

    SECTION 7: COVERS AND SHROUDS GENERAL NOTE: The blower cover is notched at the point where the governor rod and anti-lash spring pass through it. In the course of tearing down a complete engine for ser- This allows the cover to be removed without discon- vice and repairs, the engine shrouds and covers may need to necting the governor rod from the governor arm.

  • Page 32: Section 8: Ignition System

    SECTION 8: IGNITION SYSTEM GENERAL SPARK PLUG The ignition system typically used on GN-190, GN-191 and The spark plug should be cleaned and regapped periodi- GN-220 engines is a solid-state (breakerless) type. The system cally. The plug should be replaced every 100 hours of operation utilizes a magnet on the engine flywheel to induce a relatively or once annually, whichever comes first.

  • Page 33: Flywheel Installation

    SECTION 8: IGNITION SYSTEM Use a commercially available flywheel puller to remove the flywheel from the engine tapered shaft. FLYWHEEL INSTALLATION: Align the keyway in the flywheel with the woodruff key on the crankshaft. Install the flywheel, the conical washer and the starter cup.

  • Page 34: Section 9: Valve Train

    SECTION 9: VALVE TRAIN MAJOR COMPONENTS NOTE: Whenever the rocker arm cover is removed, the cover gasket must be replaced to ensure a proper seal. Valve train components are shown in Figure 9.1 below. 2. Loosen the rocker arm jam nuts on the pivot ball studs. Then, loosen the pivot ball studs.

  • Page 35: Valve Service

    SECTION 9: VALVE TRAIN TO PREVENT EYE INJURY, ALWAYS WEAR EYE PRO- VALVE SEATS: TECTION WHEN REMOVING VALVE SPRINGS. Valve seats are not replace- able. If they are burned or pitted, they 5. Support the valves with your fingers while compressing the valve SEAT reground using a grinding springs with your thumbs on the valve spring retainer (see Figure 9.5).

  • Page 36: Valve Guides

    SECTION 9: VALVE TRAIN VALVE SERVICE (CONTINUED) VALVE SPRINGS: Inspect the valve springs (Figure VALVE GUIDES: 9.11). Measure the spring FREE Valve guides are permanently installed in the cylinder head LENGTH. Also measure the and cannot be replaced (see Figure 9.9). spring length when a known At the time of this writing, oversize valves were NOT avail- load is applied to the spring.
  • Page 37 SECTION 9: VALVE TRAIN 2. Install the valve spring washers, valve springs and valve 6. Install the push rod with either end resting on the tappet spring retainers over the valve guides. (Figure 9.15). a. Hold the valves with your fingers and use your thumbs to a.

  • Page 38: Adjusting Valve Clearance

    SECTION 9: VALVE TRAIN ADJUSTING VALVE CLEARANCE 2. When clearance is correct, hold the pivot ball stud with the allen wrench and tighten the rocker arm jam nut to the Adjust valve clearance with the engine at room tempera- specified torque with a crow's foot. After tightening the ture.
  • Page 39 NOTES...

  • Page 40: Section 10: Piston, Rings And Rod

    SECTION 10: PISTON, RINGS AND ROD GENERAL 1. Move the snap ring around until its protruding wire is aligned with the notched-out oil hole. Use needle nose pliers There are no oversize pistons or rings available for these to turn the snap ring and pull it toward you. engines.

  • Page 41: Piston Rings

    SECTION 10: PISTON, RINGS AND ROD a. A quick check for wear in (a) the wrist pin, (b) wrist pin • The OIL CONTROL RING is a three-piece assembly consisting bore in piston or (c) wrist pin bore in rod is to check for of two oil rails and an oil spacer ring.

  • Page 42: Connecting Rod

    SECTION 10: PISTON, RINGS AND ROD ASSEMBLY AND INSTALLATION ASSEMBLY: 1. Install the rings (Figure 10.4). a. Use a ring expander when installing rings into the piston grooves. Figure 10.5 — Measuring Ring End Gap CONNECTING ROD The connecting rod is manufactured of die-cast aluminum. Marks on the rod and on the rod cap must be aligned when assembling the rod to the crankshaft.

  • Page 43: Installation

    SECTION 10: PISTON, RINGS AND ROD INSTALLATION: TORQUE SPECIFICATION 1. Coat the cylinder walls with clean engine oil. CONNECTING ROD CAP BOLTS GN-190, GN-191, GN-220 2. Coat crankshaft crankpin, connecting rod bearing and 120 inch-pounds or 10 foot-pounds connecting rod cap bearing with engine oil. 3.

  • Page 44: Section 11: Crankshaft And Camshaft

    SECTION 11: CRANKSHAFT AND CAMSHAFT CAMSHAFT REMOVAL OIL PUMP ROTORS REMOVAL OF CRANKCASE COVER: CAMSHAFT LOBES Before attempting to remove the crankcase cover, remove SPRING WASHER rust, burrs and paint from the power take-off (PTO) end of the crankshaft. This will reduce the possibility of damaging the oil seal in the crankcase cover during cover removal.

  • Page 45: Camshaft Inspection

    SECTION 11: CRANKSHAFT AND CAMSHAFT CAMSHAFT INSPECTION CRANKSHAFT INSPECTION Carefully inspect the entire camshaft for wear, nicks or CRANKSHAFT PROPER: other damage. All areas indicated in figure 11.4 should be inspected. Using a commercial solvent, clean the crankshaft thor- oughly. After cleaning, inspect the crankshaft as follows: 1.

  • Page 46: Crankshaft Sleeve Bearing

    SECTION 11: CRANKSHAFT AND CAMSHAFT CRANKSHAFT SLEEVE BEARING: CRANKCASE The crankshaft bore in the crankcase is a pressure lubricated COVER oil bearing that may or may not include an additional sleeve bearing, depending on the vintage of the engine (Figure 11.6). The crankshaft bore in the crankcase cover is also a pres- sure lubricated oil bearing.

  • Page 47: Crankshaft Installation

    SECTION 11: CRANKSHAFT AND CAMSHAFT NOTE: If the crankshaft gear is spun on the crankshaft, COMPRESSION RELEASE LIFT the timing will be off. If this happens, the crankshaft GN-190 must be replaced. DESIGN LIFT = 0.027-0.055 inch (0.70-1.40mm) CAMSHAFT INSTALLATION COMPRESSION RELEASE LIFT Apply oil to camshaft bearing and to bearing bore in GN-191, GN-220...

  • Page 48: Section 12: Lubrication

    SECTION 12: LUBRICATION GENERAL OIL PICKUP ASSEMBLY The engine lubrication system serves to (a) reduce friction DESCRIPTION: between moving parts, (b) cool the engine and (c) estab- lish a negative pressure in the crankcase to prevent oil seal The oil pickup assembly consists of a plastic body and an leakage.

  • Page 49: Inspection

    SECTION 12: LUBRICATION OIL PUMP (CONTINUED) OIL PUMP ROTOR TIP CLEARANCE DESIGN CLEARANCE = 0.0000-0.0010 inch INSPECTION: (0.000-0.025mm) 1. Inspect the inner and outer rotors for damage and wear (Figure 12.4). INNER ROTOR I.D. DESIGN DIAMETER = 0.354-0.355 inch 2. Use a feeler gauge to check tip clearance of inner rotor, (9.000-9.019mm) with rotor installed on shaft in crankcase cover.

  • Page 50: Pressure Relief Valve

    SECTION 12: LUBRICATION PRESSURE RELIEF VALVE The CHECK VALVE allows excess pressure to be vented out of the crankcase and to atmosphere through the BREATHER DESCRIPTION: TUBE. Two small DRAIN HOLES allow condensed oil vapors to return to the crankcase. The ball type pressure relief valve is located in a bore of the crankcase.

  • Page 51: Inspection

    SECTION 12: LUBRICATION for (a) oil pump rotors and camshaft, (b) crankshaft, (c) gov- 3. Make sure the timing marks on the crankshaft and camshaft ernor gear assembly and (d) the oil pickup assembly. Cored gears are properly aligned. oil passages are provided from the pickup bore to the pump 4.

  • Page 52: Optional Oil Filter

    SECTION 12: LUBRICATION 14. After tightening the crankcase cover bolts, make sure the crankshaft turns freely. OPTIONAL OIL FILTER The optional oil filter is a "spin-on" type. An oil filter adapter is bolted to the oil filter pad. When installing the oil filter, coat the filter seal with engine oil.
  • Page 53 SECTION 12: LUBRICATION LOW OIL SWITCH Figure 12.13 — Low Oil Indicator Figure 12.15 — Low Oil Switch Without Optional Oil Filter TORQUE SPECIFICATION OIL FILTER ADAPTER BOLT TORQUE = 9 foot-pounds or 108 inch-pounds TORQUE SPECIFICATION LOW OIL SWITCH TORQUE = 9 foot-pounds or 108 inch-pounds LOW OIL SWITCH Figure 12.14 —...

  • Page 54: Section 13: Troubleshooting

    SECTION 13: TROUBLESHOOTING PROBLEM SOLVING CHECK IGNITION SYSTEM: See "Testing the Ignition System" in Section 8 (Page 31). INTRODUCTION: Problems that affect engine operation may be classified as CHECK FUEL SYSTEM: one of, or a combination of two or more of the following: Make sure the fuel tank has been properly filled with the •...

  • Page 55: Section 13: Troubleshooting

    SECTION 13: TROUBLESHOOTING PROBLEM POSSIBLE CAUSES REMEDY 1. Engine will not start or starts a. Fuel tank is empty. a. Fill fuel tank. with difficulty. b. Low oil level. b. Replenish oil as necessary. c. Dirty air cleaner. c. Clean or replace air cleaner element.

  • Page 56: Specifications

    SPECIFICATIONS GENERAL SPECIFICATIONS MODEL GN-190 GN-191 GN-220 BORE 2.76 inches (70mm) 2.76 inches (70mm) 2.95 inches (75mm) STROKE 1.93 inches (49mm) 1.93 inches (49mm) 1.93 inches (49mm) DISPLACEMENT 188.6cc 188.6cc 216.5cc OIL CAPACITY W/O FILTER CHANGE 21 ounces (620ml) 21 ounces (620ml) 21 ounces (620ml) WITH FILTER CHANGE 29.5 ounces (870 ml)
  • Page 57 SPECIFICATIONS CRANKCASE ASSEMBLY MODEL GN-190 GN-191 GN-220 CYLINDER BORE: DESIGN DIAMETER 2.756-2.757 inch 2.756-2.757 inch 2.953-2.954 inch (70.000-70.025mm) (70.000-70.025mm) (75.000-75.025mm) VALVE TAPPET BORE: DESIGN DIAMETER 0.295-0.296 inch 0.295-0.296 inch 0.295-0.296 inch (7.494-7.520mm) (7.494-7.520mm) (7.494-7.520mm) CRANKSHAFT SLEEVE BEARING: DESIGN DIAMETER 1.104-1.106 inch 1.104-1.106 inch 1.104-1.106 inch *(WHERE APPLICABLE)
  • Page 58 SPECIFICATIONS CRANKSHAFT MODEL GN-190 GN-191 GN-220 CRANKPIN DIAMETER: DESIGN DIAMETER 1.180-1.181 inch 1.180-1.181 inch 1.180-1.181 inch (29.99-30.01mm) (29.99-30.01mm) (29.99-30.01mm) CRANKSHAFT MAIN BEARING (FLYWHEEL END): DESIGN DIAMETER 1.102-1.103 inch 1.102-1.103 inch 1.102-1.103 inch (28.000-28.012mm) (28.000-28.012mm) (28.000-28.012mm) CRANKSHAFT MAIN BEARING (PTO END): DESIGN DIAMETER 1.102-1.103 inch 1.102-1.103 inch...
  • Page 59 SPECIFICATIONS PISTON (CONTINUED) MODEL GN-190 GN-191 GN-220 WRIST PIN BORE DIAMETER: DESIGN DIAMETER 0.708-0.709 inch 0.708-0.709 inch 0.708-0.709 inch (18.000-18.011mm) (18.000-18.011mm) (18.000-18.011mm) TOP RING GROOVE WIDTH: DESIGN WIDTH 0.059-0.061 inch 0.059-0.061 inch 0.059-0.061 inch (1.52-1.54mm) (1.52-1.54mm) (1.52-1.54mm) SECOND RING GROOVE WIDTH: DESIGN WIDTH 0.059-0.061 inch 0.059-0.061 inch...
  • Page 60 SPECIFICATIONS CAMSHAFT ASSEMBLY MODEL GN-190 GN-191 GN-220 MAIN CAMSHAFT BEARING DIAMETER (FLYWHEEL END): DESIGN DIAMETER 1.022-1.023 inch 1.022-1.023 inch 1.022-1.023 inch (25.96-25.98mm) (25.96-25.98mm) (25.96-25.98mm) MAIN CAMSHAFT BEARING DIAMETER (PTO END): DESIGN DIAMETER 1.022-1.023 inch 1.297-1.298 inch 1.297-1.298 inch (25.96-25.98mm) (32.96-32.98mm) (32.96-32.98mm) CAM LIFT: DESIGN LIFT...
  • Page 61 SPECIFICATIONS OIL PUMP (CONTINUED) MODEL GN-190 GN-191 GN-220 OIL PRESSURE RELIEF VALVE SPRING: Force required to compress 0.85-0.95 pounds 0.85-0.95 pounds 0.85-0.95 pounds spring to 1.035 inch (0.39-0.43kg) (0.39-0.43kg) (0.39-0.43kg) (26.3mm) COMPRESSION PRESSURE MODEL GN-190 GN-191 GN-220 WHILE CRANKING (COLD ENGINE) 60 psi min.
  • Page 62 Printed in U.S.A Copyright © 1999 • Generac ® Power Systems, Inc.

This manual is also suitable for:

Gn190rvGn191rvGn191hGn220rvGn220h

Table of Contents