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Contents
PRIMER BULB (DIAPHRAGM
CARBURETOR) ................................................ 11
CARBURETOR CHECK VALVE ......................... 11
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 CARBURETORS ..............
17
FUEL FITTING .................................................... 17
INLET FUEL FITTING......................................... 17
CHOKE SHAFT ................................................... 17
THROTTLE LEVER ................................................
17
IDLE SPEED ADJUSTMENT SCREW ..................
17
GOVERNORS AND LINKAGE ..............................
18
AIR VANE GOVERNORS ................................... 18
OPERATION........................................................ 18
LINKAGE INSTALLATION .....................................
18
REWIND STARTERS, ELECTRIC STARTERS
AND ALTERNATORS .............................................
20
REWIND STARTERS.......................................... 20
COMPONENTS................................................... 20
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 FIELD..................................................... 27
ARMATURE CHECK........................................... 27
TROUBLESHOOTING STARTERS .......................
27
ALTERNATORS ......................................................
28
CHECKING THE SYSTEM ................................. 28
FLYWHEEL (INSIDE-EDGE) BRAKE SYSTEM ...
29
INSIDE EDGE SYSTEM ..................................... 29
COMPONENTS................................................... 29
SERVICE ............................................................. 29
CONTROL CABLE .............................................. 30
Page
Page
GENERAL INFORMATION ......................................
1
ENGINE IDENTIFICATION................................... 1
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 SCAVENGING .............................. 4
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
OPERATION.......................................................... 7
CARBURETOR SERVICE .................................... 7
THROTTLE............................................................ 7
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 BODY .................... 10
DIAPHRAGMS .................................................... 10
INLET NEEDLE AND SEAT ............................... 11
FUEL INLET FITTING......................................... 11
Copyright © 1994 by Tecumseh Products Company
All rights reserved. No part of this book may be reproduced or transmitted, in any form or by any
means, electronic or mechanical, including photocopying, recording or by any information storage and
retrieval system, without permission in writing from Tecumseh Products Company Training Department
Manager.
Summary of Contents for AH520 -
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