Echo PB-251, Service Manual

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PB-251
1
TABLE OF CONTENTS
Page Page
1 SERVICE INFORMATION ................................... 2
1-1 Specifications .................................................. 2
1-2 Technical data ................................................. 3
1-3 Torque limits .................................................... 4
1-4 Special repairing materials ............................. 4
1-5 Service Limits ................................................. 5
1-6 Special tools ................................................... 6
2 STARTER SYSTEM ............................................. 7
2-1 Removing starter drum and rope .................... 7
2-2 Installing rewind spring ................................... 9
2-3 Installing starter drum and rope .................... 10
2-4 Increasing rope tension ................................. 11
2-5 Replacing starter pawl ................................... 11
3 IGNITION SYSTEM ........................................... 13
3-1 Troubleshooting guide .................................. 14
3-2 Testing spark ................................................. 15
3-3 Checking spark plug ..................................... 15
3-4 Replacing spark plug cap and coil ................ 16
3-5 Checking coil resistance ............................... 16
3-6 Checking ignition switch ............................... 17
3-7 Replacing ignition switch .............................. 17
3-8 Replacing ignition coil ................................... 19
3-9 Setting pole shoe air gaps ............................ 19
3-10 Checking flywheel and key ........................... 19
4 HANDLE AND CONTROL SYSTEM ................. 21
4-1 Disassembling handle and throttle control ... 22
4-2 Reassembling handle and throttle control .... 23
5 FUEL SYSTEM .................................................. 25
5-1 Cleaning air filter ........................................... 26
5-2 Checking fuel cap and fuel strainer .............. 26
5-3 Checking fuel tank and tank vent ................. 27
5-4 Replacing fuel line, tank vent line
and grommet ................................................. 28
5-5 Adjusting carburetor ..................................... 29
5-6 Testing carburetor ......................................... 31
5-7 Checking crankcase pulse passage ............. 32
5-8 Checking metering lever ............................... 32
5-9 Checking inlet needle valve .......................... 33
5-10 Checking diaphragm and others .................. 33
5-11 Replacing carburetor .................................... 34
6 BLOWER SYSTEM ........................................... 37
6-1 Disassembling fan and fan case .................. 38
6-2 Reassembling fan and fan case ................... 38
7 ENGINE ............................................................. 39
7-1 Testing cylinder compression ....................... 40
7-2 Cleaning cooling air passages ..................... 40
7-3 Checking muffler and exhaust port ............... 41
7-4 Testing crankcase and cylinder sealings ...... 42
7-5 Replacing oil seal ......................................... 43
7-6 Checking cylinder ......................................... 43
7-7 Checking piston and piston ring ................... 44
7-8 Replacing needle bearing ............................. 44
7-9 Disassembling crankcase ............................. 45
7-10 Replacing ball bearings ................................ 45
7-11 Assembling crankshaft and crankcase ......... 46
7-12 Installing piston ............................................. 46
7-13 Installing piston ring and cylinder ................. 47
7-14 Installing engine to inner fan case ................ 48
8 MAINTENANCE GUIDE .................................... 49
8-1 Service Intervals ........................................... 49
8-2 Troubleshooting guide .................................. 50
8-3 Disassembly chart ........................................ 52
INDEX .................................................................... 53