1990-1997 MerCruiser 3.0L 3.0LX Inboard Engine Manual

13 Printed in U.S.A. 90-816462 2-695 1995, Brunswick Corporation GM 4 Cylinder MARINE ENGINES

90-816462 2-695 0

90-816462 2-695 i Notice Throughout this publication, “Dangers,” “Warnings” and “Cautions” are used to alert the mechanic to special instructions concerning a particular service or operation that may be hazardous if performed incorrect- ly or carelessly. Observe them carefully! These “Safety Alerts” alone cannot eliminate the hazards that they signal. Strict compliance to these special instructions when performing the service, plus “common sense” operation, are major accident pre- vention measures. ! DANGER DANGER - Immediate hazards which will result in severe personal injury or death. ! WARNING WARNING - Hazards or unsafe practices which could result in severe personal injury or death. ! CAUTION CAUTION - Hazards or unsafe practices which could result in minor personal injury or product or property damage. Notice to Users of This Manual This service manual has been written and published by the service department of Mercury Marine to aid our dealers, mechanics and company service personnel when servicing the products described here- in. It is assumed that these personnel are familiar with the servicing procedures of these products, of like or similar products manufactured and marketed by Mercury Marine, and that they have been trained in the recommended servicing procedures for these products which include the use of mechanic’s common hand tools and the special Mercury Marine or recommended tools from other suppliers. We could not possibly know of and advise the service trade of all conceivable procedures by which a service might be performed and of the possible hazards and/or results of each method. We have not under- taken any such wide evaluation. Therefore, anyone who uses a service procedure and/or tool, which is not recommended by the manufacturer, first must completely satisfy himself that neither his nor the product’s safety will be endangered by the service procedure selected. All information, illustrations and specifications con- tained in this manual are based on the latest product information available at time of publication. It should be kept in mind, while working on the product, that the electrical system and ignition system are capable of violent and damaging short circuits or severe electrical shocks. When performing any work where electrical terminals could possibly be grounded or touched by the mechanic, the battery cables should be disconnected at the battery. Any time the intake or exhaust openings are exposed during service they should be covered to protect against accidental entrance of foreign material which could enter the cylinders and cause extensive inter- nal damage when the engine is started. It is important to note that, during any maintenance procedure, replacement fasteners must have the same measurements and strength as those removed, whether metric or customary. Numbers on the heads of the metric bolts and on surfaces of metric nuts indicate their strength. Customary bolts use radial lines for this purpose, while most customary nuts do not have strength markings. Mismatched or incorrect fasteners can result in damage or mal- function, or possible personal injury. Therefore, fasteners removed should be saved for re-use in the same locations whenever possible. Where the fasteners are not satisfactory for re-use, care should be taken to select a replacement that meets the same specifications as the original.

90-816462 2-695 ii Engine Mechanical Components Many of the engine mechanical components are designed for marine applications. Unlike automotive engines, marine engines are subjected to extended periods of heavy load and wide-open-throttle operation and, therefore, require heavy-duty components. Special marine engine parts have design and man- ufacturing specifications which are required to pro- vide long life and dependable performance. Marine engine parts also must be able to resist the corrosive action of salt or brackish water that will rust or corrode standard automotive parts within a short period of time. Failure to use recommended Quicksilver service replacement parts can result in poor engine performance and/or durability, rapid corrosion of parts subjected to salt water and possibly complete failure of the engine. Use of parts other than recommended service replacement parts, will void the warranty on those parts which are damaged as a result of the use of other than recommended replacement parts. Replacement Parts ! WARNING Electrical, ignition and fuel system components on MerCruiser Engines and Stern Drives are designed and manufactured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire or explosion. Use of replacement electrical, ignition or fuel system components, which do not comply to these rules and regulations, could result in a fire or explosion hazard and should be avoided. When servicing the electrical, ignition and fuel systems, it is extremely important that all components are properly installed and tightened. If not, any electrical or ignition component opening would permit sparks to ignite fuel vapors from fuel system leaks, if they existed.

90-816462 2-695 iii Models Covered In This Manual MODEL SERIAL NUMBER MCM 3.0L OC856451 And Above MCM 3.0L /3.0LX OC868143 And Above IMPORTANT: Refer To ”Engine Identification”, Page 3A-7 NOTICE Refer To Appropriate Stern Drive Manual fof transom assembly and stern drive unit repair.

90-816462 2-695 iv Service Manual Outline SECTION 1 - Important Information A - General Information B - Maintenance C - Troubleshooting SECTION 2 - Removal and Installation A - 4 Cylinder 3.0L / 3.0 LX (181 C.I.D.) SECTION 3 - Engine A - G.M. In-Line SECTION 4 - Electrical Systems A - Starting System B - Ignition System C - Charging System D - Instrumentation E - Wiring Diagrams SECTION 5 - Fuel System A -Fuel Pump B - MerCarb 2-Barrel SECTION 6 - Cooling and Exhaust A - Seawater Cooled Models B - Closed Cooled Models C - Exhaust Manifolds / Elbows SECTION 7 - Power Steering A - Power Steering

1 A IMPORTANT INFORMATION GENERAL INFORMATION 72000

1A - 0 - GENERAL INFORMATION 90-816462 2-695 Table of Contents Page Introduction 1A - 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How To Use This Manual 1A - 1 . . . . . . . . . . . . . . . . . Page Numbering 1A - 1 . . . . . . . . . . . . . . . . . . . . . How To Read Parts Manual 1A - 2 . . . . . . . . . . . . . . . Directional References 1A - 3 . . . . . . . . . . . . . . . . . . . Engine Rotation 1A - 3 . . . . . . . . . . . . . . . . . . . . . . . . . Engine Serial Number Locations 1A - 3 . . . . . . . . . . Engine Identification 1A - 3 . . . . . . . . . . . . . . . . . . . . . Propeller Information 1A - 3 . . . . . . . . . . . . . . . . . . . . Water Testing New Engines 1A - 4 . . . . . . . . . . . . . . Page Boat And Engine Performance 1A - 4 . . . . . . . . . . . . Boat Bottom 1A - 4 . . . . . . . . . . . . . . . . . . . . . . . . . Marine Fouling 1A - 5 . . . . . . . . . . . . . . . . . . . . . . . Weight Distribution 1A - 6 . . . . . . . . . . . . . . . . . . . . Water In Boat 1A - 6 . . . . . . . . . . . . . . . . . . . . . . . . Elevation And Climate 1A - 6 . . . . . . . . . . . . . . . . . NOTICE For information and procedures on troubleshooting, refer to SECTION 1C. NOTICE Refer to appropriate Stern Drive Service Man- ual for transom assembly and stern drive unit repair. 1A - GENERAL INFORMATION

GENERAL INFORMATION - 1A - 1 90-816462 2-695 Introduction This comprehensive overhaul and repair manual is designed as a service guide for the models previously listed. It provides specific information, including procedures for disassembly, inspection, assembly and adjustment to enable dealers and service mechanics to repair and tune these engines. Before attempting repairs or tune-up, it is suggested that the procedure first be read through to gain knowl- edge of the methods and tools used and the cautions and warnings required for safety. How to Use This Manual This manual is divided into sections which represent major components and systems. Some sections are further divided into parts which more fully describe the component. Sections and section parts are listed on the “Service Manual Outline” page following “V-8 Models Covered in This Manual” page. Page Numbering Two number groups appear at the bottom of each page. Following is an example and description. 72426

1A - 2 - GENERAL INFORMATION 90-816462 2-695 How To Read Parts Manual 841-824146 1 CYLINDER BLOCK (See Note) 1 19-34270 2 EXPANSION PLUG 8 17-35465 3 DOWEL PIN 4 22-72640 4 EXPANSION PLUG 2 23-85674 5 BEARING UNIT (SET) 1 22-48556 6 BUSHING 2 22-32802 7 PIPE PLUG 1 22-42796 8 BY-PASS VALVE 1 19-816565 9 PLUG 1 811844 10 LIFTER 12 824331 11 RETAINER 2 10-824332 12 SCREW 4 824148 13 BALANCED SHAFT 1 31-824150 14 BEARING (REAR) 1 NOTE: 841-824146 Cylinder Block includes only standard pistons, piston rings, crankshaft bearings and camshaft bearings. PART NO. REF. NO. DESCRIPTION QUAN. a A. Part Number: For part ordering - Note N.S.S. for Reference Numbers, (not shown above) - means Not Sold Separately by Mercury Marine, however, in some cases, the G.M. Part Number (for the item) is given in the De- scription Column. B. Reference Number: For part Shown on exploded parts view. C. Description: This is the most important column because it gives: 1) Description of Part: Ref. No. 1 is a Cylinder Block Assembly, No. 13 is the Balanced Shaft, etc. 2) What parts are included with a certain part: Notice how the Description of Part, for Ref. Nos. 1, and 10 through 13, are at the left side of the column. Description of Part for Ref. Nos. 2 thru 9 are indented under “Cylin- der Block”. If Ref. No. 1 (Cylinder Block) was ordered, all indented parts (Ref. Nos. 2 thru 9) would come with the part. Ref. Nos. 10 thru 14 would not come with Ref. No. 1 and would have to be ordered separately. If 2 Cylin- der Blocks were listed, both cylinder blocks would come with the indented parts. In some cases, an indented part will have another part indented under it. The second indented part will come with the first indented part. 3) Serial number break: If serial number information is listed, check product serial number to ensure that correct part is ordered. 4) Special information: Many times special information will be shown after description such as; L.H. Rotation, R. H. Rotation, Filter up, Filter Down, etc. This will help in selecting the correct part. D. Quantity: Quantity that has to be ordered. E. Special Information Block: Additional information, part numbers for gasket sets, etc. b c d e CYLINDER BLOCK AND CAMSHAFT 11 12 12 11 8 8 8 13 5 3 4 1 7 6 26790 9 10

1990-1997 MerCruiser 3.0L 3.0LX Inboard Engine Manual

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