Mercury MerCruiser GM V-8 Engine 305 CID (5.0L) & 350 CID (5.7L) Service Manual #24 (P/N 90-861327-1)
895 Pages • 12.30 MB • Instant, Printable PDF
Mercury Models Covered & Key Technical Specifications
Models: Mercury MerCruiser 305 CID (5.0L), Mercury MerCruiser 350 CID (5.7L), 350 Mag MPI, Black Scorpion
Sub-models / Variants: MCM Sterndrive, MIE Inboard, Inboard and Ski, Alpha One, Bravo One, Bravo Two, Bravo Three, Black Hawk, 5.0L EFI, 5.7L EFI, 350 Mag MPI
Model Years: 1999 (Service Manual Number 24)
Serial Numbers: 0L619000 and up (65Amp alternator break)
Technical Data:
- Engine configuration: GM V-8
- Firing order: 1-8-4-3-6-5-7-2
- Compression ratio: 9.4:1
- Idle speed (neutral): 600–650 rpm (model dependent)
- Operating rpm (WOT): 4400–4800 rpm (standard), 4200–5200 rpm (variant dependent)
- Fuel pressure: 3–7 psi (carbureted) or 30 psi (EFI/MPI)
- Spark plug gap: 0.045 in. (1.1 mm)
- Timing (idle): 8°–10° BTDC
- Oil pressure (at 2000 rpm): Minimum 30 psi (207 kPa)
- Crankcase capacity: 5.5 U.S. quarts (5.25 liters)
- Cooling system capacity: 15 U.S. quarts (14.1 liters) seawater, 20 U.S. quarts (19 liters) closed
Mercury Manual Features & Content Preview
- Official Mercury Marine publication 90-861327--1 (October 1999)
- Covers 1999 Mercury MerCruiser 305 CID (5.0L) and 350 CID (5.7L) GM V-8 marine engines, including Alpha and Bravo sterndrive and MIE inboard configurations
- Contains 895 pages of technical data, wiring diagrams, torque tables, exploded views, and diagnostic flow charts
- The definitive resource for engine series featuring Thunderbolt V ignition and multi-port fuel injection (MEFI) control systems
Engine Service and Diagnostic Coverage
When tackling complex marine engine overhauls, having exact factory specifications is non-negotiable. This manual breaks down component identification, rotational specifications, and internal lubrication clearances for crankshafts, piston assemblies, and valve trains. It thoroughly documents diagnostic testing for both carbureted and fuel-injected setups. Technicians will find pinpoint sensor reference values alongside complete trouble code charts covering MEFI 1, MEFI 2, and MEFI 3 control modules. Electrical troubleshooting is supported by comprehensive wiring routing diagrams for the starting, charging, and fuel ignition harnesses.
Cooling, Drive, and Transmission Specifications
Marine environments place massive strain on cooling and driveline components. The documentation details strict maintenance intervals for seawater and closed-loop cooling systems, highlighting winterization drain points and seawater pump teardown data. Drivetrain coverage includes service parameters for Velvet Drive and Hurth transmissions, exact shift cable adjustment procedures, and coupler spline lubrication. Cylinder head thermostat covers require 30 lb-ft of torque, while distributor hold-down clamps take 18 lb-ft. Engine compression for the 5.7L MCM must meet a minimum baseline of 100 psi. Strict adherence to these factory torque values and handling pressurized fuel systems according to the outlined procedures is essential to ensure safe vessel operation and prevent critical failures on the water.
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