1983-1993 Mercruiser Mercury GM 6-Cylinder Engines This manual only covers Engine Repair and does not cover stern drive unit repair or transom assembly. MODELS COVERED IN THIS SERVICE MANUAL: MCM 185R 229 CID (3.8L) - Serial Numbers 6289593 to 6919655 MCM 185MR 262 CID (4.3L) - Serial Numbers 6919656 to OA483580 MCM 185 Alpha One - Serial Numbers OA483581 to OB455459 MCM 175 Alpha One - Serial Numbers OB455460 to OB773242 MCM 4.3 Liter Alpha One - Serial Numbers OB773243 to OF000000 Sea Ray (Note 1) 4.3L - 2 Alpha One - Serial Numbers OB785483 to B921276 MCM 205 MR - Serial Numbers 6919687 to OA483776 MCM 205 Alpha One - Serial Numbers OA483777 to OB775129 MCM 4.3 Liter LX Alpha One - Serial Numbers OB775130 to OF000000 Sea Ray (Note 1) 4.3L - 4 Alpha One - Serial Numbers OB785981 to B922330 Note 1: Sea Ray to MerCruiser cross references are; 4.3L-2 same as MCM 4.3L 4.3L-4 same as MCM 4.3L LX This manual contains an introductory description on and procedures for the inspection, service and overhaul of its main components. General knowledge information is not included. Please read the GENERAL INFORMATION section to familiarize yourself with basic information concerning the MerCruiser engine. Read and refer to the other sections in this manual for information regarding proper inspection and service procedures. Illustrations in this manual are used to show the basic principles of operation and work procedures. This manual is intended for use by technicians who already possess the basic knowledge and skills to service MerCruiser motors and components. Persons without such knowledge and skills should attempt with caution to service any component or engine by relying on this manual only. Never attempt to perform any work with out the assistance of this service manual. Apprentice mechanics or do-it-yourself mechanics that don't have the proper tools and equipment may or may not be able to properly perform the services described in this manual. Improper repair may result in injury to the mechanic and may render the engine or sterndrive unit unsafe for the boat operator and passengers. Never attempt to work on your MerCruiser sterndrive unit or engine without a manual. Important safety precautions, service information and other data may be included. This manual covers every aspect of repair, from basic maintenance, to complete engine overhaul. QUESTIONS AND ANSWERS Q. How do I obtain this manual? A. Simply click on the download button, complete the payment and a download link is sent to your computer in seconds FOR INSTANT DOWNLOAD. Q. Once I download the repair manual how long do I have access to the manual? A. Once you download the manual you can store it on your computer forever and refer to it when maintenance and repair is necessary. Q. How does the manual appear? A. Once the manual has been downloaded it appears exactly the same as a repair manual you'd buy in stores. It includes every aspect of repair, step-by-step repair procedures, pictures, illustrations, diagrams, troubleshooting and specifications. Q. Is the repair manual model and year specific? A. YES! This is not a generic manual. Q. Does my computer need special software to view the manual? A. Your computer wont need any special software to view the manual. It is a simple PDF manual. All computers come with the necessary software already installed from the manufacture to view the manual. Q. Will the download hurt my computer? A. NO! This manual is 100 percent safe to download!