John Deere LX255 LX266 LX277 LX277AWS LX279 and LX288 Lawn Tractors Technical Manual TM1754 01APR05

SPECIFICATIONS & INFORMATION
Fastener Torques……………………………………….9
Metric Fastener Torque Values………………….9
Inch Fastener Torque Values…………………..10
O-Ring Seal Service Recommendations ……11
Face Seal Fittings With Inch Stud Ends
Torque………………………………………………….11
Face Seal Fittings With Metric Stud Ends
Torque………………………………………………….12
O-ring Face Seal Fittings…………………………13
O-Ring Boss Fittings ………………………………13
Straight Fitting or Special Nut Torques ……..13
Metric Fastener Torque Value –
Grade 7 (Special) …………………………………..14
General Information………………………………….14
Gasoline ……………………………………………….14
Gasoline Storage……………………………………15
4 – Cycle Gasoline Engine Oil ………………….15
Break-In Engine Oil – 4-Cycle Gasoline……..15
Hydrostatic Transmission and
Hydraulic Oil………………………………………….16
Gear Case Oil………………………………………..16
Gear Transmission Grease ……………………..16
Alternative Lubricants……………………………..17
Synthetic Lubricants ……………………………….17
Lubricant Storage…………………………………..17
Mixing of Lubricants ……………………………….17
Oil Filters ………………………………………………17
Coolant Specifications……………………………..17
Gasoline Engine Coolant…………………………17
Gasoline Engine Coolant Drain Interval …….18
Serial Number Locations ………………………….18
Product Serial Number ……………………………18
Gasoline Engine Serial Number Location ….18
ENGINE – KOHLER
Engine – Kohler

Specifications ………………………………………….21
General Specifications ……………………………21
Tests and Adjustments Specifications……….21
Repair Specifications………………………………22
Torque Specifications (Alphabetical)…………25
Special or Required Tools……………………….26
Other Materials………………………………………26
Diagnostics ……………………………………………..27
Engine Will Start…………………………………….27
Tests and Adjustments …………………………….28
Throttle Cable Adjustment……………………….28
Choke Cable Adjustment…………………………28
Governor Adjustment ……………………………..28
Fast Idle Speed Adjustment …………………….29
Slow Idle Screw Adjustment…………………….29
Cylinder Leak Test …………………………………30
Automatic Compression Release
(ACR) Check …………………………………………32
Crankcase Vacuum Test…………………………32
Fuel Flow Tests……………………………………..34
Oil Pressure Test……………………………………35
Fuel and Air Repair…………………………………..37
Air Intake System Components………………..37
Carburetor Removal and Installation…………37
Carburetor Inspection……………………………..38
Fuel Pump Removal and Installation…………39
Engine Repair…………………………………………..40
Engine Removal and Installation………………40
Flywheel Removal and Installation……………42
Stator Removal and Installation ……………….43
Rocker Arms Removal and Installation ……..44
Inspect Push Rod…………………………………..44
Cylinder Head Removal and Installation ……44
Valves and Springs
Removal and Installation …………………………45
Cylinder Head Inspection ………………………..46
Valves Inspection ………………………………….47
Valve Seats Recondition ………………………..47
Lap Valves ……………………………………………48
Breather Inspection ……………………………….48
Oil Pan Removal and Installation …………….48
Oil Pan Seal Removal and Installation ……..49
Crankcase Oil Seal
Removal and Installation …………………………50
Oil Pickup Inspection ……………………………. 50
Oil Pump Relief Valve Inspection ……………. 50
Oil Pump Installation……………………………… 51
Camshaft Removal and Installation ………… 51
Camshaft Inspection …………………………….. 51
Camshaft End Play Measurement ………….. 52
Hydraulic Valve Lifters
Removal and Installation ……………………….. 53
Hydraulic Valve Lifters Inspection …………… 53
Balancer Shaft Removal and Installation….. 54
Balancer Shaft Inspection………………………. 54
Governor Removal and Installation …………. 55
Governor Inspection ……………………………… 55
Piston Assembly Removal……………………… 56
Piston Assembly Disassemble ……………….. 56
Piston Inspection ………………………………….. 56
Piston Ring End Gap Measurement ………… 57
Piston Ring Side Clearance Measurement.. 57
Piston Assembly Measurement ………………. 57
Piston Assembly …………………………………… 58
Piston Installation………………………………….. 59
Crankshaft Removal and Installation……….. 60
Crankshaft and Main Bearing Inspection….. 60
Crankshaft Alignment ……………………………. 61
Cylinder Block Removal and Installation ….. 61
Cylinder Block Inspection ………………………. 62
Cylinder Bore Deglazing………………………… 62
Starting Motor ………………………………………. 62
Voltage Regulator/Rectifier…………………….. 65
ENGINE – KAWASAKI (AIR-COOLED)
ngine – Kawasaki (Air-Cooled)

Specifications ………………………………………….69
General Specifications ……………………………69
Test and Adjustment Specifications ………….69
Repair Specifications………………………………70
Torque Specifications……………………………..72
Tools and Materials ………………………………….74
Tools…………………………………………………….74
Other Materials………………………………………75
Service Parts Kits…………………………………..75
Component Location………………………………..76
Engine Components……………………………….76
Engine Oil Flow Chart …………………………….77
Carburetor Components (LX277 – FH500V).78
Carburetor Components (LX288 – FH580V).79
Theory of Operation …………………………………80
Lubrication System Operation………………….80
Diagnostics ……………………………………………..80
Engine Troubleshooting Guide…………………80
Starting Motor Troubleshooting Guide ………81
Tests and Adjustments …………………………….82
Throttle Cable Adjustment……………………….82
Choke Cable Adjustment…………………………83
Choke Plate Check and Adjustment …………83
Governor Adjustment ……………………………..84
Slow Idle Speed Adjustment ……………………85
Fast Idle Speed Adjustment …………………….86
Valve Clearance Check and Adjustment……86
Cylinder Compression Pressure Test………..87
Crankcase Vacuum Test…………………………88
Engine Oil Pressure Test ………………………..89
Fuel Pump Test……………………………………..90
Spark Test…………………………………………….91
Spark Plug Gap Adjustment …………………….91
Ignition Coil Air Gap Adjustment ………………92
Repair………………………………………………………92
Throttle Control Lever and Cable ……………..92
Muffler Removal and Installation ………………92
Air Cleaner Assembly Removal………………..93
Carburetor Removal and Installation…………94
Carburetor Disassembly and Assembly …….95
Fuel Pump Replacement…………………………96
Blower Housing Removal and Installation….96
Flywheel Removal and Installation……………97
Breather Removal and Installation ……………97
Engine Removal and Installation …………….. 98
Rocker Arm Removal and Installation ……. 100
Cylinder Head Removal and Installation…. 100
Cylinder Head Inspection……………………… 101
Recondition Valve Seats………………………. 103
Lap Valves…………………………………………. 104
Crankcase Cover
Removal and Installation ……………………… 104
Piston and Connecting Rod………………….. 104
Analyze Crankshaft and
Connecting Rod Wear …………………………. 109
Camshaft and Tappets ………………………… 109
Crankshaft and Main Bearings ……………… 110
Crankshaft Oil Seals……………………………. 112
Deglaze Cylinder Bore…………………………. 112
Resize Cylinder Bore…………………………… 112
Oil Pump Disassembly and Assembly……. 113
Oil Filter Manifold………………………………… 114
Governor Inspection and Replacement ….. 115
Governor Shaft
Inspection and Replacement ………………… 115
Stator Removal and Installation…………….. 116
Armature Removal and Installation………… 116
Starting Motor Removal and Installation…. 117
Starting Motor
Disassembly and Assembly………………….. 117
No-Load Amperage Draw and RPM Test.. 120
ENGINE – KAWASAKI (LIQUID-COOLED)
Engine – Kawasaki (Liquid-Cooled)

Specifications ………………………………………..123
General Specifications ………………………….123
Test and Adjustment Specifications ………..123
Repair Specifications…………………………….124
Torque Specifications (Alphabetical)……….126
Tools and Materials ………………………………..127
Special or Essential Tools……………………..127
Other Materials…………………………………….128
Service Parts Kits…………………………………128
Component Location………………………………129
Exterior Engine Components …………………129
Internal Engine Components………………….131
Theory of Operation ……………………………….133
Lubrication System Operation………………..133
Cooling System Operation …………………….135
Diagnostics ……………………………………………137
Engine Diagnosis …………………………………137
Engine Tests ……………………………………….140
Tests and Adjustments …………………………..143
Throttle Cable Test and Adjustment………..143
Choke Cable Test and Adjustment………….143
Governor Adjustment ……………………………144
Fast Idle Speed Adjustment …………………..144
Slow Idle Speed Adjustment ………………….145
Cylinder Compression Pressure Test………146
Valve Clearance Test and Adjustment…….146
Crankcase Vacuum Test……………………….147
Engine Oil Pressure Test ………………………148
Fuel Pump Tests ………………………………….149
Spark Test…………………………………………..150
Spark Plug Gap Adjustment …………………..150
Cooling System Pressure Test……………….151
Radiator Cap Pressure Test…………………..151
Repair…………………………………………………….152
Throttle Control Lever and
Cable Assembly …………………………………..152
Engine Removal and Installation…………….152
Muffler Removal and Installation…………….154
Air Cleaner ………………………………………….154
Carburetor Removal and Installation……….155
Intake Manifold…………………………………….157
Fuel Pump…………………………………………..158
Radiator Removal and Installation ………….159
Cooling Fan …………………………………………160
Cooling Air Duct………………………………….. 160
Thermostat…………………………………………. 160
Coolant Pump…………………………………….. 161
Overflow Reservoir ……………………………… 163
Flywheel Removal and Installation ………… 163
Rocker Arm Assembly …………………………. 163
Cylinder Head and Valves ……………………. 164
Analyze Valves …………………………………… 167
Recondition Valve Seats………………………. 168
Lap Valves…………………………………………. 168
Crankcase Cover………………………………… 169
Piston and Connecting Rod………………….. 169
Camshaft and Tappets ………………………… 173
Crankshaft and Main Bearings ……………… 174
Crankshaft Oil Seals……………………………. 175
Cylinder Block…………………………………….. 175
Deglaze Cylinder Bore…………………………. 176
Rebore Cylinder Block…………………………. 176
Oil Pump……………………………………………. 177
Breather…………………………………………….. 178
Governor……………………………………………. 179
Governor Shaft …………………………………… 179
Governor Shaft Seal ……………………………. 179
Stator Removal and Installation…………….. 180
Pulser Coils………………………………………… 180
Ignition Coils ………………………………………. 180
Ignition Module Replacement ……………….. 180
Starting Motor …………………………………….. 181
No-Load Amperage Draw and RPM Test.. 183
–
Engine – Briggs and Stratton

Specifications ………………………………………..187
General Specifications ………………………….187
Tests and Adjustments Specifications……..187
Repair Specifications…………………………….187
Torque Specifications……………………………188
Special or Essential Tools……………………..189
Diagnostics ……………………………………………190
Engine Diagnostics……………………………….190
Tests and Adjustments …………………………..196
Throttle Cable Adjustment……………………..196
Choke Cable Adjustment……………………….196
Fuel Shutoff Solenoid Test…………………….197
Compression Test ……………………………….197
Without Cylinder Leak Tester…………………197
With Cylinder Leak Tester……………………..198
Carburetor Adjustment ………………………….199
Governor Adjustment ……………………………200
Valve Clearance Adjustment …………………201
Engine Oil Pressure Test ………………………201
Ignition Armature Air Gap Adjustment……..202
Repair…………………………………………………….202
Upper Blower Housing
Removal and Installation ………………………202
Air Cleaner Removal and Installation………203
Carburetor Removal and Installation……….203
Carburetor Disassembly………………………..205
Carburetor Inspection……………………………207
Carburetor Assembly…………………………….208
Engine Removal and Installation…………….210
Cylinder Air Guides
Removal and Installation ……………………….212
Intake Manifold Removal and Installation…212
Cylinder Head Removal and Installation ….212
Cylinder Head Inspection and Repair………215
Valve Removal …………………………………….215
Valve Inspection and Repair ………………….215
Valve Guide Ream ……………………………….216
Valve Installation ………………………………….216
Piston, Rings and Rod
Removal and Installation ……………………….217
Piston Inspection………………………………….218
Connecting Rod Inspection ……………………218
Cylinder Bore Inspection ……………………….220
Cylinder Bore Honing ……………………………221
Cylinder Bore Cleaning………………………… 221
Resizing Cylinder Bore ………………………. 221
Flywheel Removal and Installation ……….. 222
Crankshaft Removal and Installation……… 223
Magneto Bearing Inspection…………………. 226
PTO and Cam Bearing Inspection…………. 227
Lubrication …………………………………………. 227
Oil Pump Removal………………………………. 228
Starting Motor Removal and Installation…. 229
Starting Motor
Disassembly and Inspection…………………. 229
Starting Motor Assembly………………………. 231
ELECTRICAL
Electrical

General Information………………………………..235
Operation and Diagnostics …………………….235
Diagnostic Information…………………………..235
Wire Color Abbreviation Chart………………..235
Reading Electrical Schematics……………….236
Common Circuit Tests…………………………..237
Conductors for 12 Volt Circuits……………….237
Specifications ………………………………………..238
General Specifications ………………………….238
Tools…………………………………………………..240
Other Materials…………………………………….240
Schematics and Wiring Harness Legends .241
Schematic and Wiring Harness Legend –
LX255 and LX266…………………………………241
Schematic and Wiring Harness Legend –
LX277…………………………………………………241
Schematic and Wiring Harness Legend –
LX279…………………………………………………242
Schematic and Wiring Harness Legend –
LX288 (SN – 090000) ……………………………243
Component Location………………………………244
Electrical Components ………………………….244
Schematics and Harnesses …………………….245
LX255 and LX266 Kohler Main
Electrical Schematic (1 of 4)…………………..245
LX277 & LX288 (FH500V and FH580V)
Main Electrical Schematic ……………………..249
LX279 (FD501V) Main
Electrical Schematic ……………………………..253
LX288 (SN -090000) B&S
Main Electrical Schematic ……………………..257
Main Wiring Harness – All Machines ……….261
LX255 and LX266 Kohler Engine
Wiring Harness…………………………………….263
LX277 and LX288 (FH500V and FH580V)
Engine Wiring Harness………………………….265
LX279 FD501V Engine Wiring Harness …..267
LX279 FD501V Engine Wiring Harness …..268
LX288 (SN -090000) B&S Engine
Wiring Harness…………………………………….270
Theory of Operation ……………………………….272
Power Circuit Operation ………………………..272
Switched Power Circuit …………………………272
Power Circuit Schematic ……………………….273
Power Circuit Diagnosis……………………….. 274
Cranking Circuit Operation …………………… 277
Cranking Circuit Schematic ………………….. 278
Cranking Circuit Diagnosis …………………… 279
Ignition Circuit Operation – LX255,
LX266, LX277 and LX288…………………….. 282
Engine Shutting OFF – LX255, LX266,
LX277 and LX288……………………………….. 282
Ignition Circuit Schematic – LX255,
LX266, LX277 and LX288…………………….. 283
Ignition Circuit Diagnosis – LX255,
LX266, LX277 and LX288…………………….. 284
Ignition Circuit Operation – LX279………….. 287
Shutting Engine Off – LX279 …………………. 287
Ignition Circuit Schematic – LX279…………. 288
Ignition Circuit Diagnosis – LX279………….. 289
Charging Circuit Operation …………………… 293
Charging Circuit Schematic ………………….. 294
Charging Circuit Diagnosis …………………… 295
PTO Circuit Operation – PTO Off…………… 298
PTO Circuit Schematic – PTO Off………….. 299
PTO Circuit Operation – PTO On…………… 300
PTO Circuit Schematic – PTO On ………….. 301
PTO Circuit Diagnosis …………………………. 302
Reverse Implement Option (RIO)
Circuit Operation…………………………………. 306
RIO Circuit Schematic …………………………. 307
RIO Circuit Diagnosis ………………………….. 308
Low Oil Pressure Light Circuit Operation… 312
Low Oil Pressure Schematic…………………. 313
Low Oil Pressure Circuit Diagnosis ……….. 314
Headlight Circuit Operation…………………… 316
Headlight Circuit Schematic………………….. 317
Headlight Circuit Diagnosis…………………… 318
Fuel Shutoff Solenoid Circuit Operation …. 320
Fuel Shutoff Solenoid Circuit Schematic … 321
Fuel Shutoff Solenoid Circuit Diagnosis …. 322
Coolant Temperature Light
Circuit Operation – LX279 …………………….. 325
Coolant Temperature Light
Circuit Schematic – LX279 ……………………. 326
Coolant Temperature Light
Circuit Diagnosis…………………………………. 327
Tests and Adjustments …………………………. 329
Common Circuit Tests …………………………. 329
Ground Circuit Test……………………………… 329
Battery Voltage and Specific
Gravity Test ……………………………………….. 330
Battery – Charge …………………………………..331
Battery – Load Test……………………………….331
Regulated Amperage Test …………………….332
Regulated Voltage Test…………………………333
Unregulated Voltage Output Test……………333
Regulator/Rectifier Test…………………………334
Flywheel Magnet Test …………………………..335
Starting Motor Solenoid Test………………….335
Starter Loaded Amperage Draw Test………335
Starting Motor No-Load Amperage &
RPM Tests…………………………………………..336
Spark Test – LX255, LX266 &
LX288 (SN -090000) …………………………….337
Ignition Coil Test –
LX277 & LX288 (SN 090001 -)……………….338
Armature Air Gap Adjustment ………………..338
Ignition Module Test – LX279 …………………339
Ignition Coil Test – LX279………………………339
Pulser Coil Test – LX279 ……………………….340
Spark Plug Cap Test – LX279…………………340
Light Switch Test………………………………….341
PTO/RIP Switch Test ……………………………341
Seat Switch Test ………………………………….342
RIO Switch Test …………………………………..342
Brake/Neutral Start Switch Test ……………..343
Fuel Shutoff Solenoid Switch Test ………….343
Oil Pressure Switch Test ……………………….343
Coolant Temperature Switch Test –
LX279…………………………………………………344
RIO Switch Adjustment …………………………345
Electric PTO Clutch Test……………………….346
Repair…………………………………………………….347
Electric Clutch Removal and Installation ….347
Connector Body – Blade Terminals …………348
Metripack® Connector…………………………..348
Starting Motor………………………………………350
Kawasaki FD501V Engine –
Starting Motor………………………………………350
Kohler, Kawasaki FH500V/FH580V, and
B&S Engines – Starting Motor ………………..353
Power Train – Hydrostatic

Specifications ………………………………………..359
General Specifications ………………………….359
Tests and Adjustments Specifications……..359
Repair Specifications…………………………….359
Torque Specifications……………………………360
Tools and Materials ………………………………..360
Other Materials…………………………………….360
Component Location………………………………361
Transaxle Case Halves …………………………361
Center Case and Valves ………………………362
Motor and Piston Pump…………………………363
Control Shaft ……………………………………….364
Reduction Gears, Differential, and Axles …366
Brake …………………………………………………367
Belt Drive and Idlers – 2WS ……………………368
Belt Drive and Idlers – AWS……………………369
Brake Pedal and Linkage ……………………..370
Forward and Reverse/Cruise
Control Linkage ……………………………………371
Forward and Reverse Pedals and Linkage
(Exploded View) …………………………………..372
Cruise Control Lever and Linkage
(Exploded View) …………………………………..373
Rear Axle – AWS ………………………………….374
Theory of Operation ……………………………….375
Controls and Linkage Operation……………..375
Foot Control – Neutral Position……………….375
Foot Control – Forward (Maximum) …………375
Foot Control – Neutral……………………………376
Foot Control – Forward (Maximum) …………377
Foot Control – Reverse (Maximum) …………377
Brake Depressed – Maximum…………………378
Brake Linkage ……………………………………..378
Foot Control – Reverse (Maximum) …………379
Brake Depressed – Maximum…………………379
Cruise Control ……………………………………..380
Cruise Control – Off Position…………………..380
Cruise Control –
Maximum Speed Position………………………381
Hand Control ……………………………………….381
Hand Control – Neutral ………………………….382
Hand Control – Forward…………………………383
Hand Control – Reverse…………………………384
Hydrostatic System Operation………………..385
Gear Power Flow………………………………… 386
Transaxle Brake………………………………….. 388
Diagnostics…………………………………………… 389
Machine Will Not Move Forward or
Reverse …………………………………………….. 389
Noisy Operation………………………………….. 393
Machine Creeps………………………………….. 395
Machine Moves In One Direction Only …… 397
Erratic Speed……………………………………… 398
Machine Does Not Achieve Full
Ground Speed ……………………………………. 400
Park Brake Does Not Hold
Machine On Hill ………………………………….. 402
Brake Switch Will Not Engage………………. 404
Cruise Control Does Not
Maintain Ground Speed……………………….. 406
Transaxle Whines When Brake Is Used…. 407
Tests and Adjustments …………………………. 407
Hydrostatic Transaxle
Bleeding Procedure …………………………….. 407
Neutral Creep Adjustment ……………………. 407
Forward and Reverse Pedal
Height Adjustment ………………………………. 409
Hand Lever Rod Adjustment…………………. 409
Brake Linkage Adjustment……………………. 410
Neutral Return Arm Bearing Adjustment … 410
Cruise/Hand Control Lever
Tension Adjustment…………………………….. 410
Repair…………………………………………………… 411
Transaxle Removal and Installation –
2WS Models ………………………………………. 411
Transaxle Removal and Installation –
AWS Models………………………………………. 418
Transaxle Disassembly………………………… 423
Center Case Removal …………………………. 426
Center Case Disassembly ……………………. 429
Pump Shaft Removal…………………………… 429
Control Shaft Removal…………………………. 430
Brake Shaft Removal…………………………… 431
Transaxle Assembly ……………………………. 431
Traction Drive Belt
Removal and Installation ……………………… 439
Traction Drive Belt Tensioner Assembly…. 442
Control Pedals and Linkage………………….. 443
Intermediate Shaft ………………………………. 443
Neutral Return Arm……………………………… 444
Cruise Control Lever (2WS Model)………… 445
Cruise Control Lever (AWS Model) ……….. 446
Hand Control Lever (Optional)
(2WS Model) ……………………………………….448
Hand Control Lever (Optional)
(AWS Model)……………………………………….448
Brake Pedal and Linkage ………………………450
Brake Rod Removal and Installation ……….451
STEERING
Steering

Specifications ………………………………………..455
LX255, LX266, LX277, LX279 and LX288
2 Wheel Steering (2WS)………………………..455
LX277 and LX279 All Wheel Steering
(AWS)…………………………………………………455
Repair Specifications…………………………….456
Tools and Materials ………………………………..456
Service Equipment and Tools ………………..456
Other Materials…………………………………….456
Component Location………………………………457
Steering Wheel – 2WS…………………………..457
Front Axle – 2WS………………………………….458
Steering Components – AWS …………………459
Steering Components – LX277 AWS……….460
Steering Wheel – AWS ………………………….461
Steering Wheel – LX277 AWS………………..462
Front Axle – AWS………………………………….463
Rear Axle and Tie Rods – AWS………………464
Rear Axle and Tie Rods – LX277 AWS ……465
Theory of Operation ……………………………….466
Steering System – 2WS …………………………466
Steering System – AWS…………………………467
Diagnostics ……………………………………………468
Steering System – Front Steering……………468
Steering System – Rear Steering…………….468
Steering Wander ………………………………….469
Lash (Lost Motion) at Steering Wheel ……..469
Steering Wheel Turns Farther In
One Direction ………………………………………469
Wheels Will Not Track Straight……………….470
Tests and Adjustments …………………………..471
Toe-In Adjustment – AWS Front ……………..471
Steering Wheel Centering ……………………..471
Toe-In Adjustment – AWS Rear………………472
Rear Wheel Alignment – AWS………………..473
Repair…………………………………………………….474
Steering Gear Removal…………………………474
Steering Gear Installation………………………479
Front Axle Removal, Disassembly, and
Inspection……………………………………………485
Front Axle Assembly and Installation ………488
Front Wheel Spindle Lubrication …………….492
Front Axle Pivot Lubrication …………………..492
Rear Steering Pivot Lubrication – AWS ……492
Front Wheel Removal and Installation……. 492
Front Wheel Bearing
Removal and Installation ……………………… 493
Rear Wheel Removal and Installation ……. 493
ATTACHMENTS
Attachments

Specifications ………………………………………..497
Adjustment Specifications ……………………..497
Repair Specifications…………………………….497
Tools and Materials ………………………………..498
Tools…………………………………………………..498
Other Materials…………………………………….498
Component Location………………………………499
38-Inch Mower Deck …………………………….499
42-Inch Mulching Mower Deck ……………….503
42-Inch Convertible Mower Deck ……………507
44-Inch Piranha Mower Deck ………………..512
48-Inch Convertible Mower Deck ……………517
54-I