Lycoming IO-390-D Series User manual

© 2020 Avco Corporation. All Rights Reserved.
Engine Maintenance Manual
(Principal Manual)
IO-390-D Series
March 2020
Part No. MM-IO-390-D Series

IO-390-D Series
Engine Maintenance Manual
Lycoming Part Number: MM-IO-390-D Series
Contact Us:
Mailing Address:
Lycoming Engines
652 Oliver Street
Williamsport, PA 17701 USA
Phone:
Factory
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Direct:
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[phone]
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Visit us Online: www.lycoming.com
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Lycoming recommends that owners of this manual sign up for email notification on the Technical
Publications page of our website https://www.lycoming.com/contact/knowledge-base/publications.
By submitting your email address, you will receive notification whenever Lycoming publishes a new
or revised technical publication, including any revisions to this Engine Maintenance Manual.

IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved Airworthiness Limitations
March 2020 Page i
IO-390-D Series Engine Maintenance Manual
AIRWORTHINESS LIMITATIONS
1. General
This Airworthiness Limitations chapter sets forth each mandatory replacement time,
inspection interval, and related procedure required for type certification. The
Airworthiness Limitations chapter is FAA approved and specifies maintenance required
under §§ 43.16 and 91.403 of the Federal Aviation Regulations (FAR) unless an
alternative program has been FAA-approved.
2. Mandatory Inspection - Fuel Injector Lines
At every 100 hours of operation and after any maintenance has been done on the engine
where the fuel injector lines have been disconnected, moved or loosened, examine the
fuel lines per the "Fuel Line Inspection" procedure in Chapter 73-10 of this manual.
3. Mandatory Inspection - Exhaust Valve and Guide
At every 1000 hours of operation for IO-390-D Series engines, examine the exhaust valve
and guide conditions. Refer to the section "Exhaust Valve and Guide Inspection" in
Chapter 72-30.

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IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved Record of Revisions
March 2020 Page iii
IO-390-D Series Engine Maintenance Manual
RECORD OF REVISIONS
Revision
Revision
Date
Revised
By
Revision Description
Original
Original Release of Maintenance Manual –
Part No. MM-IO-390-D Series

IO-390-D Series Engine Maintenance Manual
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© 2020 Avco Corporation. All Rights Reserved Service Document List
March 2020 Page v
IO-390-D Series Engine Maintenance Manual
SERVICE DOCUMENT LIST
NOTICE: The following is a list of service documents referenced in or incorporated into the
information in this manual. Always refer to the latest revision of any service document
(including any supplements) for changes or additional information. Supplements to a
service document contain information relevant to the service document but not yet
added to the service document.
The latest revision of all service documents in this list can be downloaded from our
website https://www.lycoming.com/contact/knowledge-base/publications.
To narrow the search parameters and limit the number of returns, enter only the
numerical portion of the service document number in the Search box on the website.
Number
Incorporation
Date
Subject
S.B. 201
03/20
Inspection of Crankshaft Flange
S.B. 225
03/20
Replacement of Valve Rocker Thrust Washers
S.B. 240
03/20
Mandatory Parts Replacement at Overhaul and
During Repair or Maintenance
S.B. 342
03/20
Fuel Line (Stainless Steel Tube Assy.) and Support
Clamp Inspection and Installation
S.B. 357
03/20
Engine Inspection After an Engine Has Been Soaked
or Immersed
S.B. 369
03/20
Engine Inspection after Overspeed
S. B. 388
03/20
Procedure to Determine Exhaust Valve and Guide
Condition
S.B. 398
03/20
Recommended Corrective Action for Use of
Incorrect Fuel
S.B. 399
03/20
Action to Take If Loss of Oil Pressure
S.B. 401
03/20
Recommendations for Aircraft Struck by Lightning
S.B. 475
03/20
Crankshaft Gear and Crankshaft Gear End Inspection
and Corrective Action
S.B. 480
03/20
Oil, Oil Filter, Oil Pressure Screen, and Oil Suction
Screen Servicing
S.B. 505
03/20
Inspection of Crankshaft I.D. for Corrosion
S.B. 533
03/20
Recommended Action for Sudden Engine Stoppage,
Propeller/Rotor Strike or Loss of Propeller/Rotor
Blade or Tip
S.I. 1009
03/20
Recommended Time Between Overhaul Periods
S.I. 1011
03/20
Tappets and Lifters
S.I. 1012,
Supplement 1,
Supplement 2
03/20
Counterweights and Rollers on Engine Models

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SERVICE DOCUMENT LIST (CONT.)
Number
Incorporation
Date
Subject
S.I. 1014
03/20
Lubricating Oil Recommendations
S.I. 1029
03/20
Tightening Procedures for Crankcase Thru-Studs and
Bolts
S.I. 1037
03/20
Approved Pistons, Rings and Cylinders for Use on
Lycoming Aircraft Engines
S.I. 1042
03/20
Approved Spark Plugs
S.I. 1043
03/20
Spark Plug Heli-Coil®Insert Replacement
S.I. 1047
03/20
Inspection and Reconditioning Procedures for Nitride
Hardened Steel Cylinders
S.I. 1059
03/20
Pre-Lubrication of Parts Before Assembly
S.I. 1060
03/20
Push Rod Identification
S.I. 1070
03/20
Specified Fuels for Spark Ignited Gasoline Aircraft
Engine Models
S.I. 1080
03/20
Maintenance Items for Special Attention
S.I. 1098
03/20
Propeller Flange Bushing Location
S.I. 1129
03/20
Methods of Checking DC Alternator and Generator
Belt Tension
S.I. 1141
03/20
Replacement of Worn Starter Ring Gears
S.I. 1143
03/20
Counterweight Bushing Inspection, Replacement,
and Special Tooling Upgrades
S.I. 1154
03/20
FAA-Approved Starters and Alternators
S.I. 1172
03/20
Adjustable Oil Pressure Relief Valve Installation and
Valve Seat Repair or Replacement
S.I. 1191
03/20
Cylinder Compression Check
S.I. 1241
03/20
Pre-oil the Engine Prior to Initial Start
S.I. 1267
03/20
Piston Pin Plug Usage
S.I. 1285
03/20
Non-Destructive Testing of Lycoming Engine Parts
S.I. 1290
03/20
Repair of Oil Leakage at Crankcase Thru-Stud
Locations; Assembled and Unassembled Engines.
S.I. 1301
03/20
Identification of Primer and Fuel Injector Lines
S.I. 1304
03/20
Engine Nameplate Replacement
S.I. 1316
03/20
Valve Seat Refacing on Oil Cooler Bypass Valves
S.I. 1324
03/20
Crankshaft Oil Seals
S.I. 1340
03/20
Piston Pin Identification
S.I. 1343
03/20
Set Screw for Propeller Governor Idler Shaft

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March 2020 Page vii
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SERVICE DOCUMENT LIST (CONT.)
S.I. 1409
03/20
Lycoming Engines P/N LW-16702 Oil Additives
S.I. 1425
03/20
Suggested Maintenance Procedures to Reduce the
Possibility of Valve Sticking
S.I. 1427
03/20
Field Run-In and Break-In
S.I. 1458
03/20
Connecting Rod Bolts (Identification and
Installation)
S.I. 1462
03/20
Propeller Oil Control Leak Test Procedure
S.I. 1485
03/20
Exhaust Valve and Guide Identification Procedure
S.I. 1492
03/20
Piston Pin Plug Wear Inspection
S.I. 1514
03/20
Roller Tappets Part Information Update
S.I. 1529
03/20
Hydraulic Lifter and Tappet Body Part Numbers
S.I. 1530
03/20
Engine Inspection in Particulate-Laden Environments
S.I. 1535
03/20
Counterweight and Roller Removal, Inspection, and
Installation
S.I. 1566
03/20
Lycoming Engines Approves the Use of Safety Cable
S.I. 1569
03/20
Installation of Lycoming Electronic Ignition System
(EIS)
S.I. 1575
03/20
New Connecting Rod Bushing
S.L. L114
03/20
Reciprocating Engine and Accessory Maintenance
Publications
S.L. L171
03/20
General Aspects of Spectrometric Oil Analysis
S.L. L180
03/20
Engine Preservation Guidelines for Active and Stored
Aircraft
S.L. L192
03/20
Spark Plug Fouling
S.L. L197
03/20
Recommendations to Avoid Valve Sticking
S.L. L221
03/20
Warranty Repair of Precision Airmotive Corporation
Fuel Control Products
S.L. L247
03/20
Shelf Life Requirements
S.L. L253
03/20
Warranty Repair of AVStar Fuel Systems, Inc. Fuel
Control Products
S.L. L272
03/20
Release of New Silicone Rocker Cover Gaskets

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TABLE OF CONTENTS
Subject Page
Title Page _______________________________________________________________________
Airworthiness Limitations................................................................................................................... i
Record of Revisions............................................................................................................................iii
Service Document List........................................................................................................................ v
Table of Contents............................................................................................................................... ix
Abbreviations and Acronyms ......................................................................................................... xix
Introduction...................................................................................................................................... xxi
Required Maintenance ................................................................................................. 05-00
—Required Maintenance ............................................................................................................. 1
—General..................................................................................................................................... 1
—List of Tools for Service and Maintenance.............................................................................. 1
—Table 1 - Tools for Service and Maintenance...................................................................... 1
—Time Between Overhaul (TBO)............................................................................................... 2
—Safety Precautions - Before Engine Maintenance.................................................................... 3
—Maintenance Practices.............................................................................................................. 3
—General Engine Inspection Criteria.......................................................................................... 5
—Requirements for Engine Maintenance.................................................................................... 5
—Approved Parts......................................................................................................................... 5
Time Limits / Service Checks....................................................................................... 05-10
—Engine Inspection Schedule for IO-390-D Series Engines...................................................... 7
Required Engine Inspections for IO-390-D Series Engines...................................... 05-20
—Engine Inspections.................................................................................................................... 9
—Visual Inspection for IO-390-D Series Engines ....................................................................... 9
—Operational Leak Check Sheet for IO-390-D Series Engines................................................. 15
—10-Hour Initial Engine Inspection for IO-390-D Series Engines ........................................... 16
—25-Hour Engine Inspection for IO-390-D Series Engines...................................................... 17
—50-Hour Engine Inspection for IO-390-D Series Engines...................................................... 20
—100-Hour or Annual Engine Inspection for IO-390-D Series Engines................................... 23
—400-Hour Engine Inspection for IO-390-D Series Engines.................................................... 28
—500-Hour Engine Inspection for IO-390-D Series Engines.................................................... 30
—1000-Hour Engine Inspection for IO-390-D Series Engines.................................................. 31

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Subject Page
Cleaning ......................................................................................................................... 05-30
—Cleaning Guidelines................................................................................................................ 33
—Table 1 - Cleaning Guidelines for Engine Components..................................................... 34
—Crankshaft Cleaning................................................................................................................ 36
—Crankshaft Counterbore Cleaning........................................................................................... 36
—Crankshaft Gear Cleaning....................................................................................................... 37
—Tappet Cleaning...................................................................................................................... 38
—Crankcase Cleaning................................................................................................................. 38
—Grit-Blasting............................................................................................................................ 38
—Soft Carbon Removal.............................................................................................................. 39
—Hard Carbon Removal ............................................................................................................ 40
—Cylinder Cleaning................................................................................................................... 40
—Piston Cleaning....................................................................................................................... 41
—Injection Nozzle Cleaning....................................................................................................... 41
—Steel, Aluminum, or Magnesium Parts Cleaning.................................................................... 42
—Spark Plug Cleaning................................................................................................................ 43
—Lead Deposit Removal............................................................................................................ 43
—Volcanic Ash Removal ........................................................................................................... 43
—Cleaning Guidelines for a Soaked Engine .............................................................................. 44
—Cleaning Method for Non-Destructive Testing ...................................................................... 44
Unscheduled Corrective Maintenance........................................................................ 05-50
—Lightning Strike - After a Lightning Strike ............................................................................ 47
—Engine Overspeed................................................................................................................... 47
—Table 1 - Overspeed Values for IO-390-D Series Engines................................................. 48
—Incorrect Fuel or Fuel Contamination..................................................................................... 50
—Soaked Engine......................................................................................................................... 51
—Engine on Fire or Near a Fire.................................................................................................. 52
—Hydraulic Lock ....................................................................................................................... 52
—Volcanic Ash/Particulate Contamination................................................................................ 53
—Table 2 - Action to Take in Volcanic Ash Conditions........................................................ 54
—Valve Sticking......................................................................................................................... 55
—Oil Starvation/Sudden Loss of Oil Pressure ........................................................................... 55

IO-390-D Series Engine Maintenance Manual
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IO-390-D Series Engine Maintenance Manual
Subject Page
Unscheduled Corrective Maintenance (Cont.)........................................................... 05-50
—Metal Contamination of the Lubrication System.................................................................... 56
—Propeller Strike, Sudden Engine Stoppage or Loss of a Propeller Blade Tip......................... 56
—Engine Inspection Checklist After Propeller Strike for IO-390-D Series Engines............. 56
—Cleaning Methods for Non-Destructive Testing..................................................................... 64
Servicing - Replenishing............................................................................................... 12-10
—Refueling................................................................................................................................. 65
—Oil Level Check ...................................................................................................................... 65
—Oil Consumption..................................................................................................................... 66
—Oil Type and Viscosity ........................................................................................................... 66
—Add Oil to the Engine ............................................................................................................. 66
—Oil Leak Check ....................................................................................................................... 67
—Oil Servicing Schedule............................................................................................................ 67
—Table 1 –Oil Servicing Schedule ...................................................................................... 78
—Oil Change Procedure............................................................................................................. 68
—Engine Pre-Oil Procedure ....................................................................................................... 69
—Oil Suction Screen Removal/Inspection/Cleaning/Installation............................................... 71
—Oil Pressure Screen Removal/Inspection/Cleaning/Installation ............................................. 72
—Oil Filter Replacement............................................................................................................ 73
—Oil Filter Inspection ................................................................................................................ 73
—Identification of Metallic Solids After Oil Servicing.............................................................. 74
—Visual Inspection of the Oil Filter Element, Oil Pressure Screen, and Oil Suction Screen.... 74
—Table 2 - Guidelines for Identification of Metal Particulates
and Chips & Corrective Action.......................................................................... 76
—Table 3 - Guidelines for Particle Quantity and Size on Oil Filter or Oil Suction Screen.. 78
—Recommended Corrective Action Options............................................................................. 80
—Table 4 - Recommended Corrective Action Options......................................................... 80
—Oil Contamination Check........................................................................................................ 81
Fault Isolation................................................................................................................ 12-30
—Recommended Approach to Fault Isolation............................................................................ 83
—Fault Isolation Guide............................................................................................................... 83
—Table 1 - Fault Isolation Guide.......................................................................................... 83
—Table 2 –EIS Troubleshooting Guide ............................................................................... 97

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Subject Page
Engine Removal and Return to Service...................................................................... 72-00
—Engine Removal Prerequisites.............................................................................................. 101
—Engine Removal Procedure................................................................................................... 101
—Engine Installation Preparation Requirements...................................................................... 103
—Table 1 - Materials and Procedures to Prepare a Serviced Engine for Installation ......... 103
—Operational Ground Check ................................................................................................... 104
—Idle Speed and Mixture Adjustment ..................................................................................... 104
—Engine Mount Inspection...................................................................................................... 105
—Return to Service Procedure ................................................................................................. 106
Engine Disassembly....................................................................................................... 72-05
—Table 1 - Sequence of IO-390-D Series Engine Disassembly Procedures ...................... 107
Engine Assembly........................................................................................................... 72-10
—Corrosion Prevention ............................................................................................................ 113
—Painting the Engine and Engine Components....................................................................... 113
—Table 1 - Paint Stripping and Painting Guidelines for Components................................ 113
—Limits and Clearances........................................................................................................... 115
—Inspections ............................................................................................................................ 115
—Engine Assembly Procedure................................................................................................. 116
—Table 2 - Sequence of IO-390-D Series Engine Assembly Procedures........................... 116
—Engine Assembly Checklist .................................................................................................. 122
Propeller Flange Bushing Replacement...................................................................... 72-15
—Propeller Flange Bushing Removal ...................................................................................... 127
—Propeller Flange Bushing Installation................................................................................... 127
Crankcase Maintenance............................................................................................... 72-20
—Crankcase Inspection Before Disassembly........................................................................... 129
—Connecting Rod Removal..................................................................................................... 129
—Crankcase Disassembly......................................................................................................... 130
—Tappet, Main Bearing, and O-Ring Removal.................................................................. 131
—Propeller Governor Drive Removal / Disassembly
(Engines with Front-Mounted Propeller Governor Drives) ............................................ 133
—Oil Plug Removal............................................................................................................. 134
—Crankshaft Idler Gear Shaft Removal.............................................................................. 134
—Piston Cooling Nozzle Removal...................................................................................... 135
—Crankshaft Disassembly........................................................................................................ 135
—Counterweight Removal .................................................................................................. 136

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Subject Page
Crankcase Maintenance (Cont.).................................................................................. 72-20
—Crankcase Dimensional Inspection....................................................................................... 138
—Crankshaft Inspection ........................................................................................................... 140
—Alignment Dowel Inspection................................................................................................ 149
—Crankshaft Bearing Surface Inspection................................................................................. 150
—Camshaft Inspection.............................................................................................................. 151
—Connecting Rod Inspection................................................................................................... 152
—Connecting Rod Bushing Replacement ................................................................................ 154
—Connecting Rod Parallelism / Squareness Check................................................................. 156
—Tappet Inspection.................................................................................................................. 157
—Crankshaft Assembly............................................................................................................ 157
—Alignment Dowel Replacement....................................................................................... 157
—Crankshaft Gear Installation ............................................................................................ 158
—Expansion Plug Installation ............................................................................................. 160
—Solid-Ring Crankshaft Oil Seal Installation..................................................................... 161
—Connecting Rod Installation............................................................................................. 163
—Counterweight Installation............................................................................................... 164
—Piston Cooling Nozzle Installation (if removed) .................................................................. 166
—Crankshaft Idler Gear Shaft Installation ............................................................................... 166
—Oil Plug Installation (if removed)......................................................................................... 167
—Tappet Assembly Installation................................................................................................ 168
—Crankshaft Bearing and O-Ring Installation......................................................................... 168
—Propeller Governor Drive Installation
(Engines with Front-Mounted Propeller Governor Drives).................................................. 169
—Camshaft Assembly and Installation..................................................................................... 171
—Crankshaft Installation.......................................................................................................... 173
—Crankcase Assembly............................................................................................................. 174
—Crankshaft Oil Seal Installation............................................................................................ 179
—Crankshaft Idler Gear Installation......................................................................................... 181
—Crankshaft Endplay Clearance Check................................................................................... 181
—Propeller Oil Control Leak Test............................................................................................ 182
—Propeller Governor Removal
(Engines with Front-Mounted Propeller Governor Drives).................................................. 184
—Propeller Governor Installation
(Engines with Front-Mounted Propeller Governor Drives).................................................. 184
—Crankshaft-to-Camshaft Timing Check................................................................................ 184

IO-390-D Series Engine Maintenance Manual
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Page xiv March 2020
IO-390-D Series Engine Maintenance Manual
Subject Page
Accessory Housing Maintenance................................................................................. 72-25
—Accessory Housing Removal................................................................................................ 185
—Oil Pump Removal................................................................................................................ 186
—Oil Pump Installation............................................................................................................ 186
—Fuel Pump Plunger Removal ................................................................................................ 187
—Fuel Pump Plunger Inspection.............................................................................................. 187
—Fuel Pump Plunger Installation............................................................................................. 187
—Accessory Housing Installation ............................................................................................ 187
—Propeller Governor Replacement
(Engines with Rear-Mounted Propeller Governor Drives)................................................... 189
Cylinder Maintenance .................................................................................................. 72-30
—General.................................................................................................................................. 191
—Visual Cylinder Inspection.................................................................................................... 191
—Cylinder Compression Check ............................................................................................... 192
—Table 2 - Summary of Cylinder Compression Check Results and Corrective Action..... 196
—Intercylinder Baffle Inspection ............................................................................................. 197
—Cylinder Borescope Inspection............................................................................................. 198
—Table 3 - Borescope Inspection Steps, Results and Corrective Action............................ 199
—Exhaust Valve and Guide Inspection.................................................................................... 199
—Cylinder Removal ................................................................................................................. 204
—Piston Removal..................................................................................................................... 208
—Cylinder Assembly Inspection.............................................................................................. 209
—Piston Inspection................................................................................................................... 213
—Piston Ring Replacement...................................................................................................... 217
—Piston Installation.................................................................................................................. 218
—Intake Valve Replacement .................................................................................................... 219
—Exhaust Valve Replacement ................................................................................................. 220
—Cylinder Installation.............................................................................................................. 221
—Corrective Action for Valve Sticking ................................................................................... 227
—Intake and Exhaust Valve Guide Replacement..................................................................... 228
—Intake and Exhaust Valve Seat Replacement........................................................................ 228
—Barrel Glaze and Varnish Removal from Interior Cylinder Barrel....................................... 229
—Heli-Coil®Replacement........................................................................................................ 229

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IO-390-D Series Engine Maintenance Manual
Subject Page
Lubrication System Maintenance................................................................................ 72-50
—Oil Pressure Adjustment ....................................................................................................... 231
—Oil System Inspection........................................................................................................... 231
—Oil Line Inspection................................................................................................................ 231
—Oil Line Replacement ........................................................................................................... 232
—Oil Level Gage Tube and Assembly Removal...................................................................... 232
—Oil Level Gage Tube and Assembly Installation.................................................................. 232
—Oil Pressure Relief Valve Removal ...................................................................................... 233
—Oil Pressure Relief Valve Inspection.................................................................................... 233
—Oil Pressure Relief Vale Installation..................................................................................... 233
—Oil Cooler Bypass Valve Removal....................................................................................... 234
—Oil Cooler Bypass Valve Cleaning....................................................................................... 234
—Oil Cooler Bypass Valve Installation.................................................................................... 234
—Oil Pressure Screen Housing Removal................................................................................. 235
—Oil Pressure Screen Housing Installation.............................................................................. 235
—Oil Filter Base Removal........................................................................................................ 235
—Oil Filter Base Installation.................................................................................................... 235
—Oil Sump Removal................................................................................................................ 236
—Oil Sump Installation............................................................................................................ 236
—Propeller Governor Oil Line Removal
(Engines with Rear-Mounted Propeller Governor Drives)................................................... 239
—Propeller Governor Oil Line Installation
(Engines with Rear-Mounted Propeller Governor Drives)................................................... 239
Accessory Drives ........................................................................................................... 72-60
—Accessory Drive Inspection.................................................................................................. 241
—Propeller Governor Drive Replacement
(Engines with Rear-Mounted Propeller Governor Drives)................................................... 241
Electrical System Maintenance.................................................................................... 72-70
—Wiring Inspection.................................................................................................................. 243
—Alternator Belt Inspection..................................................................................................... 243
—Alternator Belt Tension Check/Adjustment.......................................................................... 243
—Alternator and Bracket Removal........................................................................................... 246
—Alternator and Bracket Installation....................................................................................... 246

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IO-390-D Series Engine Maintenance Manual
Subject Page
Electrical System Maintenance (Cont.)....................................................................... 72-70
—Alternator Belt Replacement................................................................................................. 247
—Starter Replacement.............................................................................................................. 247
—Starter Ring Gear Support Replacement............................................................................... 248
—Starter Ring Gear Replacement............................................................................................. 249
Induction System Maintenance.................................................................................... 72-80
—Induction System Inspection................................................................................................. 251
—Intake Pipe Replacement....................................................................................................... 251
—Fuel Drain Valve Adapter Assembly Inspection .................................................................. 252
Engine Fuel and Control –Distribution Maintenance.............................................. 73-10
—Fuel System Inspection......................................................................................................... 253
—Fuel Line Inspection.............................................................................................................. 255
—Table 1 - Corrective Action for Fuel Lines...................................................................... 258
—Fuel Injector Leak Check...................................................................................................... 259
—Fuel System Inspection Checklist......................................................................................... 259
—Fuel Line Replacement ......................................................................................................... 261
—Fuel Injector Replacement .................................................................................................... 264
—Injection Nozzle Replacement.............................................................................................. 265
—Injection Nozzle Fuel Flow Check........................................................................................ 267
—Fuel Manifold Replacement.................................................................................................. 267
—Fuel Pump Replacement ....................................................................................................... 269
Ignition System Maintenance....................................................................................... 74-20
—Spark Plugs ........................................................................................................................... 271
—Spark Plug Removal.............................................................................................................. 271
—Ignition Lead Inspection ....................................................................................................... 272
—Spark Plug Inspection ........................................................................................................... 272
—Spark Plug Fouling................................................................................................................ 273
—Spark Plug Port Seal Inspection............................................................................................ 274
—Spark Plug Cleaning.............................................................................................................. 274
—Spark Plug Gap Setting......................................................................................................... 274
—Spark Plug Rotation .............................................................................................................. 275
—Spark Plug Installation.......................................................................................................... 275

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Subject Page
Ignition System Maintenance (Cont.).......................................................................... 74-20
—Ignition Harness Removal..................................................................................................... 276
—Ignition Harness Inspection .................................................................................................. 276
—Ignition Harness Installation................................................................................................. 277
Electronic Ignition System / Magneto Maintenance.................................................. 74-30
—Lycoming Electronic Ignition System (EIS)......................................................................... 279
——EIS Inspection.................................................................................................................. 279
——EIS Replacement.............................................................................................................. 280
——EIS Removal .................................................................................................................... 280
——EIS Installation................................................................................................................. 281
——Install the Drive Gear (Magneto Gear)........................................................................ 281
——Internally Time the EIS ............................................................................................... 282
——Mount the EIS on the Engine ...................................................................................... 283
——EIS Timing Check............................................................................................................ 284
—Traditional Magnetos (Optional)...........................................................................................284
—Magneto Inspection.......................................................................................................... 284
—Magneto-to-Engine Timing Check .................................................................................. 284
—Magneto Adjustment Procedure....................................................................................... 287
—Magneto Replacement Procedure .................................................................................... 288
Exhaust System Inspection........................................................................................... 78-00
—Exhaust System Inspection....................................................................................................291
Appendix A______________________________________________________________________
—Stud Replacement ................................................................................................................. 293
—Fin Stabilizer Installation...................................................................................................... 294
—Install Stud at Oil Filter Pad (if Required)............................................................................ 295
—Install the Fitting for the Manifold Pressure Line in Cylinder #3......................................... 296

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