1983-1990 MerCruiser R/MR/Alpha One/Alpha One SS Sterndrive Units OEM Service & Repair Manual
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Number 6 Printed in U.S.A. 90-12934--2 1097 1997, Mercury Marine Sterndrive Units R·MR·Alpha One· Alpha One SS SERVICE MANUAL
90-12934--2 1097 0 90-12934--2 90-12934--2
90-12934--2 1097 i Models Covered in This Manual Transom Assemblies Model Serial Number MC 120R/140B/185R/488R/898R/228R/260R 6216687 – 6849289 MC 120MR/140MR/170MR/185MR/190MR/200MR/ 230MR/260MR/300 Tempest MR 6849290 – 0A471374 MC Alpha One/Alpha One SS 0A471375 and Above Sterndrive Units MC 120R-260R Original Ratio Ratio If Serviced With 13:21 Gears Serial Number 1.98:1 1.94:1 6237861-6854392 1.84:1 1.81:1 6225577-6862701 1.65:1 1.62:1 6268065-6810537 1.50:1 1.47:1 6229158-6847029 1.32:1 1.29:1 6231571-6663947 MC 120 MR - 300 TEMPEST MR Original Ratio Ratio If Serviced With 13:28 Gears Serial Number 1.98:1 1.94:1 6854393-0A476746 1.84:1 1.81:1 6862702-0A470164 1.65:1 1.62:1 6810538-0A475786 1.50:1 1.47:1 6847030-0A479506 MC ALPHA ONE / ALPHA ONE SS Original Ratio Ratio If Serviced With 13:28 Gears R.H. Serial Number L.H. Serial Number 1.98:1 1.98:1 0A476747 and Above 0C881740 and Above 1.84:1 1.84:1 0A470165 and Above 0C884040 and Above 1.65:1 1.65:1 0A475787 and Above 0C881790 and Above 1.50:1 1.50:1 0A479507 and Above 0C852908 and Above 1.32:1 1.32:1 0A613927 and Above Alpha One SS 1.50:1/1.32:1 1.50/1.32:1 0A545004 and Above
90-12934--2 1097 ii Sea Ray Sterndrive Units and Transom Assembly (Oyster White) Original Ratio Ratio If Serviced With 13:21 Gears Serial Number 1.98:1 0B803866-0C348031 1.84:1 0B800854-0C343526 1.50:1 0B796473-0C340666 1.32:1 0B804807-0C340030 Transom Assembly 0B815811-0C340333 When making repairs to Sea Ray (Oyster White) sterndrives, follow procedures as outlined for corresponding MerCruiser models as shown in the cross-reference chart below. Sea Ray MerCruiser 3.0L 3.0L Alpha One 4.3L2 4.3L Alpha One 4.3L4 4.3LX Alpha One 5.7L 5.7L Alpha One SRX 5.7L 350 Magnum Alpha One SRX 7.4L 454 Magnum Alpha One
90-12934--2 1097 iii Notice Throughout this publication, “Warnings” and “Cau- tions” (accompanied by the International HAZARD symbol ! ) are used to alert the mechanic to special instructions concerning a particular service or opera- tion that may be hazardous if performed incorrectly 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 prevention 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. IMPORTANT: Indicates information or instruc- tions that are necessary for proper operation and/or maintenance. Notice To Users of This Manual This service manual has been written and published by the service department of the manufacturer to aid our dealers’ mechanics and company service per- sonnel when servicing the product described herein. It is assumed that these personnel are familiar with the servicing procedures of this product, or like or similar products. That they have been trained in the recommended servicing procedures of these prod- ucts which includes the use of mechanics’ common hand 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 all possible hazards and/or result of each method. We have not undertaken any such wise 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. As required, revisions to this manual will be sent to all dealers contracted by us to sell and/or service these products.
90-12934--2 1097 iv Replacement Parts ! WARNING Electrical system components on gasoline engines and MerCruiser 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 system compo- nents, which do not comply to these rules and regulations, could result in a fire or explosion hazard and should be avoided. When servicing electrical systems, it is extremely important that all components are properly installed and tightened. If not, any electrical component opening would permit sparks to ignite fuel vapors from fuel system leaks, if they exist or develop. ! WARNING Electrical system components on diesel engines are not external ignition protected. DO NOT STORE OR UTILIZE GASOLINE ON BOATS EQUIPPED WITH THESE ENGINES, UNLESS PROVISIONS HAVE BEEN MADE TO EXCLUDE GASOLINE VAPORS FROM ENGINE COMPART- MENT (ref: 33 CFR). Failure to comply could result in fire, explosion and/or severe personal injury.
Important Information Removal, Installation and Adjustments Sterndrive Unit Transom Assembly Power Trim Steering Systems Corrosion Protection 1 2 3 4 5 6 7 90-12934--2 1097 v Service Manual Outline Section 1 - Important Information A - Important Information B - Maintenance C - Troubleshooting Section 2 - Removal, Installation and Adjustments A - All Models Section 3 - Sterndrive Unit A - Drive Shaft Housing B - Gear Housing - MR/Alpha One/Alpha One SS C - Gear Housing - I-R D - Gear Housing - Alpha One Counter Rotation Section 4 - Transom Assembly A - Service Procedures Requiring Minor Disassembly B - Service Procedures Requiring Major Disassembly Section 5 - Power Trim A - Oildyne Power Trim Pump (Plastic Reservoir) B - Oildyne Power Trim Pump (Aluminum Reservoir) C - Prestolite Power Trim Pump D - Trim Cylinders E - Dual Power Trim Control F - Auto Trim II Section 6 - Steering Systems A - Power Steering B - Manual Steering Section 7 - Corrosion Protection A - All Models
GENERAL INFORMATION IMPORTANT INFORMATION A 1 23253
IMPORTANT INFORMATION - 1A-1 90-12934--2 1097 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 parts are listed on page. Page Numbering Two number groups appear at the bottom of each page. Following is an example and description. Introduction This comprehensive overhaul and repair manual is designed as a service guide for the MerCruiser models previously listed. It provides specific information, including procedures for disassembly, inspection, assembly and adjustment, to enable dealers and service mechanics to repair these products. Before attempting repairs, it is suggested that proce- dure first be read through to gain knowledge of the methods and tools used and the cautions and warnings required for safety. Special Product Information During production of these models, special product improvements and changes have been made to increase product reliability and performance. Such changes to a sterndrive assembly component(s) are covered in the “Special Information” portion of the appropriate sterndrive assembly section. (Refer to the section “Index”.) Serial number breaks are provided, where applicable, for ease of identification. Directional References Front of boat is bow; rear is stern. Starboard side is right side; port side is left side. In this service manual, all directional references are given as they appear when viewing boat from stern, looking toward bow. Propeller Rotation Propeller rotation for sterndrive can be right hand or left hand rotation as viewed from the aft end of the propeller. 22266 22267 Right Hand Rotation Left Hand Rotation
1983-1990 MerCruiser R/MR/Alpha One/Alpha One SS Sterndrive Units OEM Service & Repair Manual is an essential guide for technicians and DIY enthusiasts for the routine service, maintenance, and repair of the MerCruiser sterndrive units. This comprehensive manual covers service requirements for MerCruiser R/MR/Alpha One/Alpha One SS sterndrive units, including detailed sections for MC 120R/140B/185R/488R/898R/228R/260R Serial Numbers - 6216687 thru 6849289, MC 120MR/140MR/170MR/185MR/190MR/200MR/230MR/260MR/300 Tempest MR Serial Numbers - 6849290 thru 0A471374, and MC Alpha One/Alpha One SS Serial Numbers 0A471375 and above.
This repair manual provides clear procedures and illustrations for the inspection, service, and overhaul of key sterndrive components. It is designed to serve both professional mechanics and skilled DIY enthusiasts by demonstrating the basic principles of operation and step-by-step work procedures.
Please note that this manual is intended for technicians with fundamental repair skills. Those without sufficient expertise should exercise caution and avoid attempting any work without proper guidance outlined in this manual.
Improper repair or service without the necessary tools and safety precautions can result in injury and render the engine or sterndrive unit unsafe. Therefore, always adhere to the safety instructions provided and rely on this manual for precise service information.
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Appearance: The manual is formatted like a traditional repair manual, complete with step-by-step procedures, illustrations, diagrams, troubleshooting tips, and detailed specifications.
Model and Year Specific: This manual is specifically tailored for the 1983-1990 MerCruiser R/MR/Alpha One/Alpha One SS sterndrive units and is not a generic guide.
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1983-1990 MerCruiser R/MR/Alpha One/Alpha One SS Sterndrive Units OEM Service & Repair Manual