Yamaha Marine 6U/8U (6CM, 6CEM, 8CM, and 8CEM) Outboard Motor Service Manual (P/N 6H6-28197-Z5-11)

This 592-page PDF combines three Yamaha factory repair publications plus a one-page library identification sheet. It contains the 300-page 6U/8U Service Manual (P/N 6H6-28197-Z5-11; cover ID LIT-18616-01-34, 1st Edition, May 1995), the 201-page F6Z/F8Z Service Manual (68T-28197-ZA-11; P/N LIT-18616-02-19, 1st Edition, April 2000, including two final wiring sheets), and the 90-page T8PH/T8PR Supplementary Service Manual (69G-28197-1A-1X; P/N LIT-18616-02-31, 1st Edition, October 2000). Yamaha prepared these manuals primarily for its dealers and trained mechanics, and states that users need a basic understanding of mechanical and electrical service work.

Covered Models and Workshop Content

• 6U/8U two-stroke models: Manual-start 6CM and electric-start 6CEM use approval code 6H6; manual-start 8CM and electric-start 8CEM use 6G1. Starting blocks are S030589/L319132/UL700192 for 6CM, S100787/L401307 for 6CEM, S056590/L340981/UL702817 for 8CM, and S102231/L403196/UL750491 for 8CEM.

• F6Z/F8Z four-stroke models: Covers F6AMH/F6MH (68R) and F8CMH/F8MH (68T), both with S000101 and L300101 starting blocks. These are tiller-control, manual-start configurations; service data covers one- and two-lighting-coil systems.

• T8/FT8 variants: Adds FT8DMH/T8MH, FT8DE/T8ER, FT8DEP/T8PR, and FT8DEHP/T8PH, all code 69G. Their L/X blocks start at 350101/650101, 400101/700101, 500101/750101, and 550101/850101, respectively. The supplement separates manual- and electric-start tiller models, remote-control electric-start models, and the T8PH/T8PR power-tilt configurations.

• Powerhead, fuel, and control repair: The two-stroke chapters cover power-unit removal, carburetor and fuel-pump service, reed valves, cylinder/piston/crankshaft inspection, recoil starter repair, and idle, ignition-timing, and throttle-link adjustment. Four-stroke sections add timing-belt and gear timing, valve-clearance adjustment, cylinder-head and oil-pump work, valve-guide and seat repair, and crankshaft plain-bearing clearance checks.

• Lower-unit repair: Procedures cover unit removal, water-pump and impeller service, propeller-shaft and bearing-housing work, dog-clutch and gear inspection, seals, drive shaft, shift cam, leak testing, shimming, and forward/reverse backlash measurement. The T8 supplement provides different shim-selection procedures for USA/Canada and other markets.

• Bracket and power-tilt service: The base manuals address steering handles and cables, upper cases, swivel and clamp brackets, mount rubbers, and steering friction. T8 material adds power-tilt fluid checks, valve and pump disassembly, motor and armature tests, cylinder service, system bleeding, and unit removal/installation.

• Electrical diagnosis and drawings: Coverage includes CDI ignition, charge and pulser coils, oil-pressure control, emergency warning, starter circuits, and one- versus two-lighting-coil charging tests. Named drawings include the 6CM/8CM manual-start and 6CEM/8CEM electric-start wiring diagrams, both F6MH/F8MH lighting-coil diagrams, and the T8PH and T8PR schematics. Fault charts trace no-start/rough-idle, shifting, battery-charging, and peak-voltage problems.

Factory Data and Required Tooling

The specification sections supply component-specific torque tables, fluid capacities and lubricant data, wear limits, machining and inspection clearances, fuel-pump test data, gear-shim selections, and resistance and peak-voltage values. Identified Yamaha tools include the YU-91022-B CDI tester, YM-01253/90890-04019 valve spring compressor, 90890-06706 backlash indicator, and YB-06560/90890-06560 power-tilt wrench.

Model-Specific Cautions and Scope

The F6/F8 crankcase instructions warn that fitting the oil seals after tightening the crankcase bolts can damage the seals. Lower-unit leak testing must not exceed the manual’s specified pressure because excess pressure can also damage seals; the T8 power-tilt section requires lint-free handling to prevent hydraulic malfunctions.

Match the motor’s model plate and starting serial block rather than buying by horsepower or year alone. The T8 supplement does not stand alone; Yamaha directs it to be used with the F6Z/F8Z base manual. This set does not establish blanket 1996–2006 coverage for every Yamaha 6 hp or 8 hp outboard. Gasoline vapor, rotating and spring-loaded components, electrical testing, and stored hydraulic pressure call for proper marine-shop isolation, ventilation, and personal protection.