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Table of Contents
Troubleshooting
Related Manuals for Toro Lawn-boy
Summary of Contents for Toro Lawn-boy
- Page 1 R-TEK/DURAFORCE (E) ENGINE SERVICE MANUAL Table of Contents – Page 1 of 1 PREFACE SAFETY SPECIFICATIONS SPECIAL TOOLS TROUBLESHOOTING MAINTENANCE CARBURETOR FUEL SYSTEM IGNITION SYSTEM REWIND STARTER ENGINE PIVOTING ZONE START BRAKE ELECTRIC START SYSTEM (120 VOLT) ELECTRIC START SYSTEM (12 VOLT)
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Page 3: About This Manual
We hope that you find this manual a valuable addition to your service shop. If you have questions or comments regarding this manual, please contact us at the following address: The Toro Company Consumer Service Department 8111 Lyndale Ave. So. Minneapolis, MN 55420-1196 The Toro Company reserves the right to change product specifications or this manual without notice. -
Page 4: Table Of Contents
TABLE OF CONTENTS TABLE OF CONTENTS SAFETY ................. 1 SPECIFICATIONS . - Page 5 TABLE OF CONTENTS CARBURETOR ................17 Identification .
- Page 6 TABLE OF CONTENTS REWIND STARTER ............... .37 Operation .
- Page 7 TABLE OF CONTENTS ELECTRIC START SYSTEM (12 VOLT) ............53 Troubleshooting .
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Page 8: Safety
Avoid injury due to inferior parts... Avoid lacerations and amputations... Use only Toro/Lawn-Boy original parts to ensure that Stay clear of all moving parts whenever the engine is important safety criteria are met. running. Treat all normally moving parts as if they were moving whenever the engine is running or has the Avoid injury to bystanders... -
Page 9: Specifications
4 or 5HP Compression ratio 5.8:1 Compression Approximately 115 psi. Service limit 80 psi. Carburetor Dual-circuit Lawn-Boy with fixed jets, float type with primer and choke Fuel required Unleaded regular (87 octane R+M/2):2-cycle oil Mix ratio 32:1 50:1 Recommended Oil... -
Page 10: Engine Fastener Torque Requirements
SPECIFICATIONS Item DuraForce R tek Choke Manual, butterfly type Fuel filter In-tank and in-carburetor Piston rings Cast iron, semi-keystone top ring. Second ring is rectangular. Anti-rotation pin in piston. Piston Permanent mold, high silicon aluminum Engine Fastener Torque Requirements Item DuraForce R tek Bolt, Head... -
Page 11: Standard Torques
140 - 200 in. lbs. (16 - 22 Nm) Carburetor Specifications Item DuraForce R tek Type Lawn-Boy, float type, dual-circuit, with primer and choke Body Material Minlon Seat material Brass with Viton tipped needle. Both are replaceable. Inlet Needle “Pop-Off” Pressure 5 psi (.7 kg/cm2) (Wet) -
Page 12: Special Tool Requirements
SPECIAL TOOLS SPECIAL TOOL REQUIREMENTS Listing Description Order From Part Number Comments/Use Air Gap Gauge Toro 604659 Sets .010” (.25 mm) gap between flywheel and coil Piston Ring Compressor TOR 4089 Compresses piston rings to allow installation into the cylinder... -
Page 13: Troubleshooting
TROUBLESHOOTING TROUBLESHOOTING Engine Will Not Start When “Cold” Possible Causes Remedies Fuel tank is empty Fill with clean, fresh, properly-mixed, unleaded fuel Bad fuel Drain tank and float bowl. Fill the tank with clean, fresh, unleaded, properly-mixed fuel. Fuel filter plugged Replace fuel tank Air cleaner plugged Wash and re-oil air cleaner element (DuraForce only) -
Page 14: Engine Will Not Produce Spark
TROUBLESHOOTING Engine Will Not Produce Spark Possible Causes Remedies Spark plug wire disconnected Reconnect spark plug wire Spark plug fouled or damaged Replace spark plug Spark plug wire damaged Replace CD pack Coil kill wire grounded Locate and eliminate the unwanted ground Ignition coil failed Replace CD pack Flywheel magnets weak... -
Page 15: Engine Lacks Power
TROUBLESHOOTING Engine Lacks Power Possible Causes Remedies Dull blade Sharpen or replace blade, mower only Housing choked with grass and debris Clean housing thoroughly, mower only Plugged exhaust system Clean exhaust ports Muffler plugged Clean or replace muffler Flywheel key sheared Replace flywheel key Carburetor dirty Clean carburetor... -
Page 16: Engine Overheats
TROUBLESHOOTING Engine Overheats Possible Causes Remedies Cylinder head cooling fins clogged Clean fins thoroughly Restricted carburetor jets Clean carburetor and jet Improper gas to oil mix ratio Ensure mixture is correct Cooling air intake plugged Remove foreign material and clean Engine Vibrates Excessively Possible Causes Remedies... -
Page 17: Engine Pre-Ignites
TROUBLESHOOTING Engine Pre-Ignites Possible Causes Remedies Wrong spark plug - too hot Install the correct type of spark plug Low quality fuel (old or stale) Replace with fresh, unleaded regular fuel Carbon buildup in engine Decarbon engine and muffler Excessive alcohol in fuel Replace with fresh unleaded fuel having no more than 10% ethanol Sheared flywheel key... -
Page 18: Engine Stalls
Drain fuel tank and replace with fresh, unleaded regular fuel having the correct oil mixture Fuel/oil mixture too rich Drain fuel tank and fill with fuel of correct mixture Wrong Oil Use Toro 2-cycle oil, Lawn-Boy DuraForce oil, or NMMA TCW3 approved oil... - Page 19 THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 20: Maintenance
MAINTENANCE Recommended Maintenance Schedule Frequency Item Comments 5 Hours Fasteners Check blade and engine mounting fasteners frequently. Keep all nuts, bolts, and screws tight to ensure safe operation. 25 Hours Housing (Mower only.) Remove the buildup of grass clippings and dirt. (Self-propelled mower only.) Clean grass clippings and debris under drive belt mechanism cover and drive belt. -
Page 21: Air Filter (Mower Only)
MAINTENANCE Air Filter (Mower Only) Note: Be sure filter is properly seated in air box and is not puckered (allowing direct passage of air and dirt to carburetor). Once every season, or every 50 hours, clean the air filter housing and element. Do so more frequently under dusty conditions. -
Page 22: Cleaning The Exhaust System (Lawn Mower)
MAINTENANCE Cleaning the Exhaust System (Lawn Mower) Warning: Disconnect the spark plug wire to prevent accidentally starting the engine. 1. (Mower) Using a 1/2" drive with a 15/16" socket, remove the blade nut that secures both the mulch fan and blade to the engine. Use heavy-duty gloves to hold the blade while removing the nut. -
Page 23: Cleaning The Exhaust System (Snowthrower)
MAINTENANCE Cleaning the Exhaust System Reassembling Exhaust System (Snowthrower) (Mower Only) 1. Remove the muffler (see Figure 10.) Clean as 1. Install the exhaust pipe into the engine base (see needed. Figure 12). Figure 12 16547-006 Figure 10 0893-012 2. The cover on the exhaust portion of the engine base uses a high temperature silicone to seal the 2. -
Page 24: Carburetor
CARBURETOR Identification The E series engines use two versions of the primer start carburetor. One with an air filter box on the mower engines (DuraForce) and one without an air filter box on the snowthrower engines (R tek). Differences include a plug in the snowthrower carburetor vent passage and some minor differences in the throttle shafts, jetting and throttle valve bleed hole. -
Page 25: Troubleshooting
CARBURETOR Troubleshooting Engine Starts Hard Possible Causes Remedies Primer malfunction Repair or replace as necessary No fuel in carburetor Add the proper fuel-oil mix Carburetor bolts loose Tighten bolts to 20 - 30 in.lbs. (2.2 - 6.2 Nm) Mislocated gaskets Loosen bolts, realign gaskets, and tighten Choke not closing fully Adjust choke or throttle/choke cable... -
Page 26: Preliminary Check
CARBURETOR Fuel Leaks From Carburetor (Leaking starts after running, stops after shutdown) Note: This condition which does NOT drain the fuel tank is called “spit-back”. Possible Causes Remedies Engine RPM out of proper range Adjust to proper range (experimentation within the RPM range may be necessary) Exhaust partially plugged Decarbon exhaust port and muffler... -
Page 27: Removal Of Duraforce Carburetor
CARBURETOR 5. Disconnect the primer tube from the carburetor 4. Disconnect the primer tube from the carburetor fitting. (See Figure 19.) fitting (see Figure 19). 6. Pull the carburetor assembly down and away from 5. Disconnect the governor spring from the the engine such that the air vane governor clears adjustment arm, and remove the choke cable. - Page 28 CARBURETOR 2. Hold the governor collar on the carburetor and lift 4. The pilot jet is located under the decal on the side the air vane/throttle shaft out of the carburetor. For of the carburetor. Remove the decal and the pilot DuraForce engines only - Lift the collar and spring jet.
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Page 29: Cleaning And Inspection
CARBURETOR 6. Remove the float hinge pin, the inlet valve needle 9. Remove the high speed jet (A) from the nozzle (B). assembly (with its clip), and the float (see Figure It is best to clean the nozzle in place. If the nozzle 25). -
Page 30: Assembly
CARBURETOR Assembly 4. Apply one drop of Loctite 242 or equivalent to the seat threads, and install a new brass inlet fuel valve seat (see Figure 31). 1. Install the high speed jet into the fuel nozzle. 2. If the nozzle has been removed, turn the carburetor over. - Page 31 CARBURETOR 8. Pressure check carburetor. Attach pump with 10. Install a new fuel bowl gasket and the fuel bowl pressure gauge to fuel inlet fitting on carburetor with the four bowl retaining screws (see Figure 35). (see Figure 33). With carburetor upside down (float up), raise float and lower to its normal position.
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Page 32: Installation
CARBURETOR 13. Install the air vane and throttle shaft into the carburetor body by very carefully pushing the shaft through the collar into the carburetor body. (See Figure 37.) 14. Push the throttle plate into the throttle shaft. (The plate only inserts one way.) If the throttle plate does not fit snugly, replace the throttle shaft. -
Page 33: Reed Valve Engine (Duraforce Engines Only)
CARBURETOR 2. Use a tachometer to check engine speed; 2900 ± 300 RPM for DuraForce engines on mowers. For R tek (piston ported) engines refer to the specification pages. Should the governor link (A) be bent or replaced, adjustment will be necessary. (See Figure 41.) Figure 39 0720-07 Piston Ported Engine... -
Page 34: Servicing The Air Filter (Duraforce Engines Only)
CARBURETOR Servicing the Air Filter (DuraForce Engines Only) 1. To remove the air filter, unsnap the wire holder on the right side of the cover the cover. Rotate the cover open. The air filter element can now be removed. If you wish to remove the cover, rotate it full open and unhook it from the hinge. - Page 35 THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 36: Fuel System
FUEL SYSTEM Operation Fuel Cap Service The E engine uses a plastic fuel tank with a non- 1. The fuel cap may not be disassembled; however, replaceable 75 micron in-tank filter screen. The filter is the vent opening on the cap and inner sealing disc welded in the bottom of the tank over a sediment should be kept free of debris. - Page 37 THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 38: Ignition System
IGNITION SYSTEM Troubleshooting Problem Possible Cause Suggested Remedy Misfiring, no firing, engine surges, Spark plug or lead wire loose Tighten plug engine dies (Note: these Spark plug in poor condition Replace plug symptoms may also be caused by fuel system problems) CD Pack air gap wrong Adjust CD Pack high tension lead loose... -
Page 39: Spark Plug Service
IGNITION SYSTEM Spark Plug Service 1. Check spark plug with the chart in this subsection and replace following the specifications given on this page. CAUTION: Do not clean plug with a sand blaster. 2. Clean with a wire brush removing the carbon buildup. -
Page 40: Cd Pack Air Gap Adjustment
IGNITION SYSTEM At slower speeds, the flywheel magnet induces a CD Pack Air Gap Adjustment smaller charge in the trigger coil. This action triggers the silicon controlled rectifier (SCR) enabling easier 1. Rotate the flywheel until the magnets are directly starting in a “retarded firing position”... -
Page 41: Flywheel Operation
IGNITION SYSTEM Flywheel Operation 3. Remove the flywheel by pulling up on the edge of flywheel while striking the flywheel nut with a soft hammer. (See Figure 55.) The flywheel is connected directly to the crankshaft (secured by a flywheel key and nut) and turns at the same speed as the crankshaft. -
Page 42: Flywheel Installation
IGNITION SYSTEM 6. Inspect the flywheel for cracks or damage and the 4. Torque flywheel nut to specifications (see Figure strength of the magnets using a iron object. 59.) Replace as necessary. (See Figure 57.) Figure 59 0893-025 Figure 57 0893-013 Flywheel Installation 1. - Page 43 THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 44: Rewind Starter
REWIND STARTER Operation 4. This recoil starter is a pressed together assembly. Due to the low cost of the assembly, we do not stock individual parts. Should the recoil fail due to The rewind starter operates through a retainer/friction something other than a starter rope, we disc that causes two engagement dogs to extend from recommend replacing the assembly. - Page 45 REWIND STARTER 2. Tie a single knot in the end of the rope; then singe the end with a lighter to prevent the knotted end of the rope from fraying (see Figure 62). Tie a simple knot in the rope to prevent too much from retracting until the starter handle is installed.
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Page 46: Engine
ENGINE General Information In this section, we will cover both versions of the E series engine. The DuraForce is a reed valve engine, and the R tek is piston ported. The design difference affects the path which the incoming fuel/air charge takes to get to the firing chamber. -
Page 47: Piston Ported Engine
ENGINE Piston Ported Engine When the piston opens the exhaust port, high-pressure exhaust gases exit the exhaust port. (See Figure 68.) Further movement of the piston towards the crankcase In a piston ported engine, there are no reed valves. uncovers the transfer port, which allows a fresh charge The fuel/air mixture enters the crankcase through a of oil/fuel mixture to enter the combustion chamber. -
Page 48: Service Tips
ENGINE Service Tips 2. Remove the entire crankshaft assembly, and discard the oil seals. 1. Cylinder/Crankcase Halves The two halves are a matched pair and cannot be exchanged between engines. Follow all cleaning and assembly procedures in this subsection. Be sure to use Loctite 515 on the mating surfaces. -
Page 49: Inspection And Repair
ENGINE 4. Remove the piston and rod assembly. Separate 3. Check all parts for wear or damage and replace if the assembly if necessary, using a snap ring pliers questionable. on the retaining ring (16). Use wrist pin knock out tool (P/N 602884) to punch out wrist pin (17). -
Page 50: Reed Valve Service (Duraforce Engines Only)
ENGINE A. Vertical scratches that appear all the way around the piston sometimes is combined with C. Cylinder damage is usually less than the discoloration (see Figure 76). Scratches all the damage to the piston. As the cylinder liner is way around the piston indicate high hours or made of harder material, it can stand more dirt ingestion. -
Page 51: Reassembly
ENGINE 3. When replacing reeds, install smooth edge down 2. Several piston and ring combinations have been centered over openings in crankcase (see Figure used. Pistons have been plated and unplated. 78), and use Loctite 271 on threads of screws. Pistons have used two keystone rings and others Torque per specifications. -
Page 52: Reinstalling External Components
ENGINE 7. Apply Loctite 515 gasket maker very thinly to the 9. Tighten the screws to specifications, tightening crankcase cover sealing surface (A), being careful only 20 in. lbs. (2.26 Nm) increments at a time not to get sealant in bearings. (See Figure 81.) while tightening modified (X) pattern. -
Page 53: Crankshaft Seal Replacement
ENGINE Crankshaft Seal Replacement Separate the crankcase from the cyclinder to replace the seals. Slide the seals off the crankshaft and clean The crankshaft seals on both the R tek and DuraForce the case mating surfaces as previously indicated. Clean engines are located right on top of a groove in the bore the block where the seal goes and the outside of the (Figure 85). -
Page 54: Pivoting Zone Start Brake
This action One of the ways the Lawn-Boy Corporation met these prevents the coil from producing the high voltage requirements was with the “zone start system.” This necessary to generate spark. -
Page 55: Disassembly
PIVOTING ZONE START BRAKE There are two versions of this brake. The function is Electric Start the same, but they contact different parts of the flywheel. Figure 88 is a diagram of the system used on recoil start engines. The brake pad engages the bottom of the flywheel. -
Page 56: Assembly
PIVOTING ZONE START BRAKE Assembly 6. Operate the blade control bail to verify that the brake mechanism stops within three (3) seconds. There is no adjustment needed after this assembly 1. If the brake mounting plate was not removed from process is completed. - Page 57 THIS PAGE INTENTIONALLY LEFT BLANK...
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Page 58: Electric Start System (120 Volt)
ELECTRIC START SYSTEM (120 VOLT) Troubleshooting Starter Motor Fails to Turn Possible Cause Correction Power not reaching product Plug another appliance into extension cord to ensure cord is OK. Starter switch malfunction Check switch using a volt/ohmmeter set for resistance. Ensure that there is continuity when the switch is depressed. -
Page 59: Starter Disassembly
ELECTRIC START SYSTEM (120 VOLT) Starter Disassembly Starter Assembly 1. Remove the pinion retaining clip by applying Assemble by reversing the disassembly process. constant pressure towards the end of the shaft on one end of the clip and working around the rest of Starter Installation the clip. -
Page 60: Electric Start System (12 Volt)
ELECTRIC START SYSTEM (12 VOLT) Troubleshooting Starter Motor Fail to Turn Possible Cause Correction Starter motor has failed Check by disconnecting the spark plug wire and starter wiring connector. Apply 12 volts directly to the starter motor. (Note: Due to the connector arrangement, it is possible that the starter motor will turn backwards during this test. -
Page 61: Starter Testing
ELECTRIC START SYSTEM (12 VOLT) 4. Remove the bolt that secures the lower bracket to 2. Remove the two screws and drag-spring stud (A) the chassis. Remove the starter. While removing, that secure the gear cover plate to the motor be careful not to move the starter side to side as housing. -
Page 62: Starter Assembly
Lawn-Boy “AX” grease to the pin. Slide the assembly on to the pin with the drag spring (A) 1. Apply a light coat of Lawn-Boy “AX” grease to the over the stud. (See Figure 102.) pinion gear, thrust washer, and driven gear prior to installation. -
Page 63: Alternator Introduction
ELECTRIC START SYSTEM (12 VOLT) Alternator Introduction charge rate, it is important to use the 120 volt charger to fully charge the battery before initial use and at the start of each season. Frequent starts or hard starting Electric start DuraForce engines are equipped with an may require using the 120 volt charger to recharge the alternator to keep the battery “topped off”. -
Page 64: Alternator Output Testing
ELECTRIC START SYSTEM (12 VOLT) Alternator Output Testing Alternator Resistance Check 1. To check output of the alternator accurately, it is 1. Disconnect the electronic cup assembly from the necessary to run the engine at operating speed, wiring harness. Connect one ohmmeter (RX-1 2900 ±... - Page 65 ELECTRIC START SYSTEM (12 VOLT) 3. Measure resistance. Reverse leads and measure resistance again. The specification is to have different resistance between the two measurements — high one way and low the opposite way. If specification is not met, replace the cup assembly.