Mercury Mariner 4hp, 5hp, 6hp 2000–2001 Outboard Motor Service Manual - (PN 90-857138R1)

• Document identity and coverage: Mercury/Mariner 4 hp, 5 hp, and 6 hp 4-Stroke outboards, starting serial number 0R000001 and above, with short- and long-shaft data. Official Mercury Marine publication 90-857138R1, May 2000; 260 PDF pages across 20 section files.
• Powerhead repair: Covers powerhead removal and installation, cylinder-head disassembly, valve-clearance adjustment, head and valve inspection, cylinder-block and crankcase teardown, piston and crankshaft inspection, and complete reassembly.
• Fuel and electrical systems: Details the external plunger/diaphragm fuel pump, 4 hp integral fuel tank, carburetor service and adjustment, CDI ignition testing, charging-system diagnosis, flywheel service, and fixed-timing checks.
• Midsection and lower-unit work: Includes clamp and swivel brackets, driveshaft housing, water tube, gear-housing removal and disassembly, water-pump and impeller service, bearing and seal replacement, shift-shaft setup, and final installation.
• Controls and starting system: Provides removal, disassembly, inspection, reassembly, and installation procedures for the shift linkage, tiller handle, and recoil starter.
• Diagrams and test references: Supplies the 4/5/6 4-Stroke Wiring Diagram, Water Flow Diagram, Oil Flow Diagram, installation drawings, cylinder-leakage analysis, exploded assembly views, torque tables, service limits, capacities, and electrical test specifications.

This factory service manual was written by Mercury Marine’s Service Department for dealer mechanics and company service personnel. It assumes familiarity with these outboards or similar products, training in recommended service procedures, and access to common hand tools plus specified service tools. In practical terms, this is shop-level repair literature rather than a beginner’s owner guide.

Coverage Details That Matter

The cover identifies Mercury and Mariner 4, 5, and 6 hp four-stroke models by starting serial number, while the specification sections separate several build changes that should be checked before parts or settings are selected. The platform uses a 123 cc single-cylinder overhead-valve powerhead. Tables distinguish 4/5 hp 1999-2000 applications, the 6 hp 2000 build, and 4/5/6 hp 2001-and-newer configurations for operating range, carburetor calibration, compression, camshaft, and valve-spring data.

Bodensee main- and pilot-jet specifications are listed separately. European 2001-and-newer models also receive model-specific pilot-mixture settings, while other later versions use non-adjustable settings.

The fuel chapter limits the integral fuel-tank coverage to 4 hp models. Electrical material covers the standard CDI ignition along with the optional lighting coil, rectifier, battery-charging circuit, and related harness connections. These distinctions help identify the system fitted to the engine instead of treating every 4/5/6 hp unit as mechanically identical.

Maintenance, Diagnosis, and Factory Tools

Routine service material covers the inspection schedule, cooling-system flushing, fuel-line and filter checks, corrosion anode inspection, NGK DCPR6E spark-plug service, engine-oil and gear-lube changes, lubrication points, and storage preparation. Separate general-information procedures address propeller selection and removal, compression testing, cylinder-leakage analysis, recovery after complete submersion, and aluminum gear-housing refinishing. Outboard installation, tilt-pin adjustment, operating angle, and the engine overspeed protection system are included as well.

Ignition diagnosis uses DVA and resistance tests for the capacitor charging coil, trigger coil, ignition coil, CDI unit, stop circuit, and oil-pressure warning circuit. Listed tools include the Multi-Meter/DVA Tester 91-99750, Magneto Analyzer 91-76032, Flywheel Holder/Puller 91-804552, Dial Indicator Gauge Kit 91-58222A1 with adapter 91-83155, Carburetor Scale 91-36392, and Piston Ring Expander 91-24697. The gearcase and powerhead chapters also identify required pullers, drivers, bearing tools, and mandrels, including tools marked no longer available.

Repair Cautions and Reference Data

The gear-housing chapter warns that the propeller-shaft and forward-gear bearings are damaged during removal, so they should not be pulled unless replacement is planned. It also calls for the original shims to remain with their assemblies. Electrical cautions explain that reversed battery polarity can damage the charging system, while the flywheel procedure warns against striking the flywheel with a hard object.

Component-specific tables provide repair torques, inspection limits, wear measurements, clearances, fuel-system settings, electrical test values, lubricant and fluid specifications, and propeller application data. Gearcase information is provided for the covered 2.15:1 housing. The color wiring diagram identifies the optional charging components alongside the CDI, stop switch, ignition coil, oil lamp, and oil-pressure switch; the water- and oil-flow drawings trace the cooling and lubrication paths through the engine.

Observe the manual’s safety alerts when securing the outboard on a stand, servicing the fuel or ignition systems, handling the spring-loaded recoil starter, or working around the propeller. These procedures assume trained service practice and the specified tools.