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General| Fuel Type | Gasoline |
|---|---|
| Cooling System | Air-cooled |
| Ignition System | Magneto |
| Starting System | Recoil |
| Engine Type | 4-stroke, single cylinder, air-cooled |
| Power | 4 HP |
| Oil Capacity | 20 oz (0.6 L) |
Locate model, serial, and date of manufacture numbers on the engine.
Explains how the first letter in a model number defines the engine type.
Identifies new short blocks and the importance of transferring original model numbers.
Recommends unleaded regular gasoline and discusses reformulated/oxygenated fuels.
Recommends detergent oil and specifies SAE grades for different temperatures.
Outlines basic minor tune-up steps for proper engine operation.
Instructions for storing engines with fuel, including safety precautions.
Step-by-step guide to safely drain fuel from the tank and carburetor.
Procedure for adding oil to the cylinder bore for storage.
Explains the function of the air cleaner in removing dust and dirt from intake air.
Describes how the air cleaner system, including pre-cleaners, cleans intake air.
Identifies the parts of the air cleaner assembly, including cover, element, and seals.
Guides on checking the air cleaner for engine performance issues like smoking or loss of power.
Recommends service intervals for polyurethane and paper filter elements.
Step-by-step instructions for disassembling the air cleaner assembly.
Details on cleaning and oiling polyurethane filter elements.
States that paper filter elements can only be serviced by replacement.
Introduces float and diaphragm carburetors and their identification.
Steps for testing engine and fuel flow to diagnose starting issues.
Explains carburetor operation at different engine speeds (choke, idle, intermediate, high).
Describes the function and types of fuel primers used on carburetors.
Explains the operation of external and remote impulse fuel pumps.
Details the operation of float carburetors and their fuel level maintenance.
Explains diaphragm carburetor operation and their advantage in severe angles.
Illustrates and labels various components of the carburetor.
Simple procedures to identify different types of Tecumseh carburetors.
Identifies dual system carburetors by primer bulb and lack of adjustment needles.
Describes Series 1 carburetors used on 2/4 cycle engines, noting venturi size and adjustability.
Explains Series 3 & 4 carburetors for higher HP engines and how to differentiate them.
Highlights diaphragm carburetor features like severe angle operation and lack of fuel bowl.
Details Series 6 carburetors for 2/4 cycle engines, noting larger venturi and fixed idle system.
Describes Series 8 carburetors with fixed main and idle circuits, and capped idle jet.
Explains Series 9 carburetors, similar to Series 8 but with a simple fixed idle system.
Describes Series 10 carburetors, identical to Series 8 but with a choke for cold starts.
Introduces the Dellorto carburetor, similar to dual system but with no adjustments.
Procedures for checking engine spark, fuel flow, and compression.
Explains carburetor pre-sets and adjustments, noting emission grade differences.
Details pre-setting mixture screws and the importance of correct torque.
Provides pre-set figures for main and idle mixture screws for different carburetor types.
Describes the procedure for adjusting main and idle mixture screws for optimal engine performance.
Step-by-step guide for disassembling float style carburetors.
Details steps for removing float bowl, needle, seat, and shutters.
Step-by-step guide for disassembling diaphragm carburetors.
Instructions for disassembling and servicing the impulse fuel pump.
Details on checking and adjusting float height for proper carburetor operation.
Guidelines for cleaning and inspecting carburetor parts after disassembly.
Inspecting throttle/choke levers, shafts, and carburetor body for wear.
Inspecting the idle and high speed mixture adjusting screws for damage.
Inspecting the fuel bowl retaining nut for passages and proper torque.
Procedures for cleaning and inspecting the fuel bowl, float, needle, and seat.
Inspecting diaphragms, gaskets, and primer bulbs for cracks or tears.
Procedures for assembling carburetor components like welch plugs and throttle shafts.
Instructions for installing new welch plugs after carburetor cleaning.
Guidance on reassembling the throttle plate, shaft, and spring, noting screw reuse.
Instructions for installing the choke shaft and plate, emphasizing correct positioning.
Procedure for installing the fuel inlet fitting, ensuring it's square.
Reassembly of adjusting screws, springs, washers, and O-rings.
Procedures for installing the inlet needle and seat assembly.
Testing the pop-off pressure of the needle and seat assembly.
Reinstalling the inlet needle and float into the carburetor.
Instructions for assembling the diaphragm cover, gaskets, and diaphragm.
Procedures for replacing the O-ring and installing the fuel bowl and nut.
Instructions for testing the impulse fuel pump.
Instructions for installing the primer retainer and bulb.
Final checks before reinstalling an overhauled carburetor.
Information on reusing parts from old carburetors for standard service carburetors.
Guidance on obtaining and installing the correct fuel inlet fitting.
Instructions for removing and installing the choke shaft and shutter.
Instructions for removing and installing the throttle lever and spring.
Removing and installing the idle speed adjustment screw.
Consulting service sections for pre-sets and adjustments before carburetor installation.
Introduces governor assembly and linkage for speed control.
Explains how governor weights control engine RPM by adjusting throttle opening.
Illustrates and labels various internal governor components.
Discusses troubleshooting governor issues like hunting and overspeeding.
Procedures for diagnosing and correcting engine overspeeding issues.
Steps to stabilize RPM and troubleshoot engine surging.
Covers governor adjustment procedures.
Step-by-step guide for adjusting the governor clamp on the governor lever.
Specific governor adjustment for short block installations prior to 1977.
Procedures for removing and servicing governor spool, gear, or shaft.
Replacing the governor spool on upset style governor shafts.
Replacing the governor gear or shaft on upset style governor shafts.
Replacing the governor shaft on retaining ring style assemblies.
Explains linkage attachment points and the importance of checking engine RPM.
Adjusting engine speed using bendable tabs on snap-in style speed controls.
Adjusting high speed RPM on medium frame vertical engines via speed control lever alignment.
Setting governed and non-governed idle RPM for proper engine operation.
Describes types of rewind starters used on Tecumseh engines.
Explains how the starter rope, pulley, and dogs engage the starter cup.
Identifies and illustrates the main components of rewind starters.
General advice on removing and inspecting starter parts for wear or breakage.
Guidance on selecting and replacing starter rope using correct part numbers and diameters.
Instructions for removing and replacing the rope retainer.
Disassembly procedure for stylized and stamped steel rewind starters.
Disassembly procedure for stylized rewind starters with plastic retainers.
General assembly procedures for rewind starters, emphasizing spring caution.
Continues assembly steps for rewind starters, focusing on retainer and spring installation.
Disassembly procedure for standard stamped steel and cast aluminum starters.
Assembly procedure for standard stamped steel and cast aluminum starters.
Continues assembly steps for standard starters, including pulley and retainer installation.
Disassembly procedure for vertical pull starters with horizontal engagement.
Assembly procedure for vertical pull starters with horizontal engagement.
Disassembly procedure for vertical pull starters with vertical engagement.
Assembly procedure for vertical pull starters with vertical engagement.
Overview of engine electrical systems: battery, starting, and charging circuits.
Explains the operation of starting and electric starter circuits.
Details how the starting circuit engages the armature and starter pinion.
Explains how alternating current is induced and generated by the flywheel magnets.
Explains AC to DC conversion using diodes and rectifiers for battery charging.
Describes half-wave rectification using a single diode.
Explains full-wave rectification using a bridge rectifier.
Identifies battery and wiring as key electrical system components.
Discusses 12-volt lead-acid batteries and their function.
Covers stranded copper wiring and important connection conditions.
Explains wire gauge measurements and their importance in electrical circuits.
Defines terms like Alternator, Ignition Coil, Rectifiers, Conductors, and Insulators.
Lists basic checks before extensive electrical system troubleshooting.
Procedures for testing the starting circuit.
Steps to check power source, starter terminal voltage, and wiring continuity.
Guidance on identifying and testing Tecumseh charging systems.
Checking the system by measuring battery voltage increase when the engine runs.
Checking the system for minimum AC voltage across a bulb.
Testing the 1 Amp add-on alternator for minimum AC voltage values.
Tests for the DC adaptor using an ohmmeter to check rectifier bridge continuity.
Performing continuity tests on rectifier bridge terminals and output leads.
Checking DC and AC output values for the 2.5 Amp DC lighting system.
Checking the 3 Amp AC lighting alternator for minimum AC voltage readings.
Checking DC and AC output for the 3 Amp DC alternator system with a diode.
Checking the 5 Amp alternator system by measuring AC voltage from the regulator-rectifier.
Determining if the alternator or regulator-rectifier is defective based on AC voltage readings.
Checking the combined 3 Amp DC and 5 Amp AC alternator system.
Measuring DC and AC voltage at specific RPMs for the combined system.
Checking minimum AC voltage readings for all models.
Checking the 7 Amp alternator system by measuring DC and AC voltage.
Diagnosing alternator or regulator-rectifier issues based on AC voltage tests.
Checking the 10 Amp alternator system by measuring AC output voltage.
Determining if the alternator assembly is defective based on AC output checks.
Checking voltage regulators using a voltmeter to ensure proper battery charging.
Checking the LOS switch function by observing spark and disconnecting the lead.
Identifying and checking the operation of lighted rocker switches with low oil shutdown.
Procedures for servicing 12V and 120V electric starters.
Procedures for removing and servicing electric starters with exposed shafts.
Procedures for disassembling and servicing electric starters with cap assemblies.
Checking pinion gears, brushes, field windings, and armature for wear or damage.
Step-by-step instructions for removing and replacing starter brushes and brush cards.
Overview of Tecumseh's brake systems and compliance standards.
Explains the bottom surface system operation for stopping the blade and engine.
Details how the brake lever forces the pad against the flywheel to stop the blade.
Explains the inside edge system where the brake pad applies to the flywheel edge.
Lists common components for both bottom surface and inside edge brake systems.
Procedures to follow if the brake system fails to kill ignition and stop the blade.
Instructions for removing the flywheel, noting brake pressure relief.
Procedures for removing and inspecting the brake lever and pad assembly.
Relieving brake pressure and removing the brake lever/pad for bottom surface systems.
Relieving brake pressure and removing the brake lever/pad for inside edge systems.
Inspecting the ignition kill switch grounding clip for proper alignment and contact.
Checking and replacing the starter interlock switch for proper engagement.
Assembling the control cable conduit and ensuring proper lever travel.
Assembling the control cable conduit against the stop in the bracket.
Ensuring proper cable conduit screw length and lever travel for inside edge systems.
Relieving brake spring tension before removing the starter bolt for bracket replacement.
Introduces solid state capacitor discharge and magneto ignition systems.
Explains the operation of solid state (CDI) ignition systems.
Details how energy is stored and released by the capacitor and SCR in CDI systems.
Explains magneto ignition systems and the role of contact points.
Provides diagrams for identifying internal, external, and solid state ignition systems.
Lists and labels the components of a magneto ignition system.
Procedures for checking spark and related ignition components.
Instructions for removing, cleaning, and adjusting spark plugs.
Lists common conditions that lead to frequent spark plug fouling.
Explains the importance of ignition timing for engine efficiency and power.
Details ignition dimensions for small and medium frame 4-cycle engines using point systems.
Procedures for removing ignition components.
Procedures for removing, cleaning, and adjusting spark plugs.
Lists common conditions that lead to frequent spark plug fouling.
Explains the importance of ignition timing for engine efficiency and power.
Details ignition dimensions for small and medium frame 4-cycle engines using point systems.
Procedure for replacing points, adjusting point gap, and timing.
Describes systems with external coils and points, including flywheel key usage.
Procedure for setting timing on solid state ignition systems using an air gap gauge.
Discusses solid state systems located under the flywheel, requiring no timing.
Provides DO NOT and PLEASE DO advice for servicing ignition systems.
Covers engine internal components like cylinder block, piston, crankshaft, and valves.
Explains the 4-cycle engine theory: intake, compression, power, and exhaust strokes.
Details the four piston strokes and their sequence in a power cycle.
Explains lubrication systems for horizontal and vertical shaft engines.
Describes the Ultra-Balance counterbalance system using a weighted shaft.
Identifies and describes major internal engine components like cylinder block, piston, rings, and crankshaft.
Lists causes and checks for engine knocking.
Lists causes and checks for engine overheating.
Lists causes and checks for engine surging or uneven running.
Lists causes and checks for excessive engine oil consumption.
Lists causes and checks for engine misfires.
Lists causes and checks for excessive engine vibration.
Lists causes and checks for breather oil passing.
Lists causes and checks for engines lacking power.
Tests and checks for engine knocking.
Tests and checks for engine overheating.
Tests and checks for engine surging or uneven running.
Tests and checks for engine misfires.
Checks for crankshaft bends, mounting bolts, and equipment balance.
Checks oil level, operation angle, RPM, and breather condition.
Checks oil level, viscosity, leaks, RPM, breather, and cooling fins.
Checks air intake, lubrication, carburetor, exhaust, and valve lash.
Procedures for engine disassembly.
General procedures for disassembling engine models.
Steps for disconnecting spark plug wire, draining oil, and removing air cleaner.
Steps for removing fuel tank, blower housing, ignition module, and flywheel.
Steps for removing cylinder cover, internal components, lifters, rod cap, and piston.
Checking cylinder for cracks, scoring, and bearing wear.
Checking piston wear, ring side clearance, and piston skirt for scoring.
Checking piston for wear, ring side clearance, and skirt condition.
Checking ring end gap and side clearance for proper oil control.
Installing connecting rods, noting piston pin hole orientation and match marks.
Inspecting crankshaft for wear, scoring, or bends, and aligning camshaft/crankshaft timing marks.
Checking camshaft bearing surfaces and lobes for wear, and cleaning parts.
Checking valve clearance, sealing, wear, and grinding valve faces.
Procedures for cutting valve seats using a Neway Valve Cutting System.
Installing shorter intake and longer exhaust valve lifters correctly.
Reaming valve guides oversize and redrilling valve spring caps.
Cleaning and installing crankcase breathers, ensuring drain holes face down.
Removing and installing top-mounted breathers, noting rubber boot design.
Mounting and removing side-mounted breathers with reed check valves.
Explains integral breathers in cylinder blocks for venting air flow.
Procedures for cleaning and inspecting cylinder covers.
Inspecting cylinder cover bearing surfaces and replacing oil seals and gaskets.
Procedures for removing and installing oil seals, noting proper depth.
Ball bearing service for H40-HM100 engines.
Removing and reinstalling ball bearings from cylinder covers and crankshafts.
Aligning the Ultra-Balance system by rotating piston to TDC.
Replacing polypropylene fans and servicing flywheel magnets.
Torque specifications for various engine components.
Engine specifications for standard point ignition models.
Engine specifications for solid state and external ignition models.
Lists Tecumseh technician handbooks for engine diagnosis and repair.
Lists foreign language technician handbooks for Tecumseh engines.
Lists available VHS video programs covering carburetor and ignition systems.
Lists special booklets providing guidance on parts manuals and failure analysis.
Assists in using and understanding the Tecumseh Master Parts Manual.
A tool for technicians to assess the cause of engine failures.
Quick reference for carburetion problems and repair procedures.
Information on identifying and troubleshooting Tecumseh ignition systems.
Depicts specialty tools offered by Tecumseh for engines and units.
Provides quick reference information found on Tecumseh wall charts.
Test procedures for electrical components using specific testers.
Describes the valve lapping tool for servicing valves.
Lists bearing drivers and bushing drivers for various engine models.
Identifies the adjustment tool for OVRM and OHV11-17 engines.
Lists the part number for the flywheel puller tool.
