This manual covers the following basic type or model numbers dependent on age of product: AH520, AH600, AV520, AV600, HSK600, TVS600. This manual covered many engines under an Old form of Identification which will need to be reviewed as well. TYPE / SPECIFICATION NUMBER 638-670 1398-1642 and Craftsman 200 Series Models. General Information, engine identification, interpretation model of number, engine care, short blocks, storage, tune up procedure, exhaust port cleaning, cycle theory of operation, operation of piston port style, operation of reed ported style with loop scavenging, terms, exhaust or scavenge phase, ports, exhaust ports, third port, reed valve, lubrication, air cleaners, carburetors, governors and linkage, air cleaners. General carburettor information, Float type carburetors, Diaphragm, carburetors, inlet needle and seat (float carburetors, needle and seat opo-off test, float height settings. Linkage installation, rewind starters, components, rope service, stylized rewind starter. Electric starters. Drive assembly service, starter checking and service, check field armature check, troubleshooting starters, alternators, checking the system, flywheel (inside-edge) brake system, Inside edge system, components service control cable. Ignition, ignition service, troubleshooting engine fails to start or starts with difficulty, engine knocks, engine misses under load, engine lack power, engine overheats, specification, and more. complete service manual consist of 68 pages in pdf format.

Contents
PRIMER BULB (DIAPHRAGM
CARBURETOR) 11
CARBURETOR CHECK VALVE11
CARBURETOR SERVICE PROCEDURE 12
EMISSIONIZED DIAPHRAGM CARBURETION13
OUTBOARD CARBURETORS 13
OUTBOARD CONTROL PANEL 14
CARBURETOR ADJUSTMENTS 15
IDLE SPEED ADJUSTMENT 15
FLOAT TYPE-FIXED MAIN, IDLE ADJUST 15
DIAPHRAGM - SINGLE AND DUAL
ADJUSTMENT 15
TROUBLESHOOTING CARBURETION 16
FLOAT CARBURETOR CHECKS 16
CHECKS FOR DIAPHRAGM 16
STANDARD SERVICE CARBURETORS17
FUEL FITTING 17
INLET FUEL FITTING17
CHOKE SHAFT17
THROTTLE LEVER 17
IDLE SPEED ADJUSTMENT SCREW 17
GOVERNORS AND LINKAGE 18
AIR VANE GOVERNORS 18
OPERATION18
LINKAGE INSTALLATION 18
REWIND STARTERS, ELECTRIC STARTERS
AND ALTERNATORS20
REWIND STARTERS20
COMPONENTS20
ROPE SERVICE 20
STYLIZED REWIND STARTER 21
VERTICAL PULL STARTER HORIZONTAL
ENGAGEMENT TYPE 22
STYLIZED REWIND STARTER WITH PLASTIC
RETAINER 23
VERTICAL PULL STARTER, VERTICAL
ENGAGEMENT TYPE 24
REWIND STARTER MOUNTED IN HOUSING 25
ELECTRIC STARTERS 26
DRIVE ASSEMBLY SERVICE 26
STARTER CHECKING AND SERVICE 27
CHECK FIELD27
ARMATURE CHECK27
TROUBLESHOOTING STARTERS 27
ALTERNATORS 28
CHECKING THE SYSTEM 28
FLYWHEEL (INSIDE-EDGE) BRAKE SYSTEM 29
INSIDE EDGE SYSTEM 29
COMPONENTS29
SERVICE 29
CONTROL CABLE 30
GENERAL INFORMATION 1
ENGINE IDENTIFICATION1
INTERPRETATION OF MODEL NUMBER 1
ENGINE CARE 2
SHORT BLOCKS 2
STORAGE: 2
TUNE-UP PROCEDURE 3
EXHAUST PORT CLEANING 3
2-CYCLE THEORY OF OPERATION 4
OPERATION OF PISTON PORT STYLE 4
OPERATION OF REED PORTED STYLE
WITH LOOP SCAVENGING4
TERMS 4
EXHAUST OR SCAVENGE PHASE 4
PORTS 4
EXHAUST PORTS 4
THIRD PORT 4
REED VALVE 4
LUBRICATION 4
AIR CLEANERS, CARBURETORS, GOVERNORS
AND LINKAGE 5
AIR CLEANERS 5
POLYURETHANE-TYPE AIR CLEANER 5
KLEEN-AIRE® SYSTEM 5
PAPER-TYPE AIR CLEANER SERVICE 5
GENERAL CARBURETOR INFORMATION 6
CARBURETOR IDENTIFICATION 6
FLOAT-TYPE CARBURETORS 6
DIAPHRAGM (PRESSURE DIFFERENTIAL)
CARBURETORS 6
OPERATION7
CARBURETOR SERVICE 7
THROTTLE7
CHOKE 8
ADJUSTING SCREWS 8
FUEL BOWL RETAINING NUT 8
CARBURETOR VENTING 8
HIGH TILT FLOAT STYLE 8
FUEL BOWL 8
FLOAT 8
INLET NEEDLE AND SEAT (FLOAT
CARBURETORS) 9
NEEDLE AND SEAT OPO-OFF TEST 9
FLOAT HEIGHT SETTINGS 9
PRIMER BULB 10
CLEANING CARBURETOR BODY10
DIAPHRAGMS 10
INLET NEEDLE AND SEAT 11
FUEL INLET FITTING11
IGNITION 31
IGNITION OPERATION (Pre- 1985
Production) 31
MAGNETO IGNITION 31
CONTACT POINTS 31
CONDENSER 31
OPERATION OF THE TECUMSEH
MAGNETO IGNITION 31
SOLID STATE IGNITION (1985 to Present32
SOLID STATE IGNITION OPERATION 32
IGNITION SERVICE 33
SPARK PLUG SERVICE 33
FLYWHEEL REMOVAL AND SERVICE33
FLYWHEEL MAGNETS 33
FLYWHEEL KEYS34
ADAPTER KEY TO FLYWHEEL ASSEMBLY34
FLYWHEEL SLEEVE 34
FLYWHEEL TORQUE34
REPLACING MAGNETO BREAKER POINTS . 34
CONDENSER CHECK
IGNITION COIL 34
IGNITION TIMING 34
FIXED TIME SPEED (EXTERNAL COIL) 36
SOLID STATE (CDI) 36
OTHER IGNITION SYSTEMS 36
OUTBOARD TIMING 38
OUTBOARD TIMING (STANDARD IGNITION) 38
OUTBOARD TIMING (SOLID STATE) 39
CYLINDERS & INTERNAL COMPONENTS41
PISTON & RING SERVICE 41
CONNECTING ROD SERVICE 42
NEEDLE BEARINGS 42
CRANKSHAFT, BEARING AND OIL SEAL
SERVICE 43
NEEDLE BEARINGS
OIL SEALS 43
ONE PIECE SEALS 43
THREE PIECE SEALS 44
OUTBOARD SEAL SERVICE 44
CYLINDERS, REEDS & COMPRESSION
RELEASE45
CYLINDER & HEAD SERVICE 45
GASKETS45
REED VALVES 45
AUTOMATIC COMPRESSION RELEASE
(DOUBLE REED TYPE) 45
AUTOMATIC COMPRESSION RELEASE
(SINGLE REED TYPE45
CYLINDER EXHAUST PORTS 46
TROUBLESHOOTING47
ENGINE FAILS TO START OR STARTS
WITH DIFFICULTY 47
ENGINE KNOCKS 47
ENGINE MISSES UNDER LOAD 48
ENGINE LACKS POWER48
ENGINE OVERHEATS 48
ENGINE SURGES OR RUNS UNEVENLY 49
ENGINE VIBRATES EXCESSIVELY 49
SPECIFICATIONS 50
ENGINE TYPE NUMBER AND LETTER
REFERENCE 50
SEARS CRAFTSMAN CROSS REFERENCE 51
TABLE OF SPECIFICATIONS 52 - 61
TABLE OF TORQUE LIMITS 62
EDUCATIONAL MATERIALS AND TOOLS 63
AVAILABLE TECHNICIAN'S HANDBOOKS 63
AVAILABLE FOREIGN TECHNICIAN'S
HANDBOOKS 63
TOOL KIT 670195D 64
TOOLS65

So as you can see it covers all you need to know, BUT best of all its the cheapest
;-)