1996–2000 Yamaha T25Y Outboard Motor Service Manual Collection (P/N LIT-18616-02-20)

Use the T25Y supplement with the included F25X base manual, as directed in its preface. The F25W and F25C/T25C books are separate editions with their own model and starting-serial-number applications; choose the relevant publication before using its specifications.

Searchable Sections and Diagram Navigation

Search, bookmarks and small labels: Text search is available in the T25Y and F25C/T25C sections. The F25X and F25W sections are not text-searchable. Embedded bookmarks provide access to all four publications and their main sections, although one legacy main-index link points outside this PDF. Small connector numbers and wire-color codes require zooming; some F25X wiring sheets also need page rotation.

The download is one printable, English-language 795-page PDF containing all four publications. The listed counts include covers, front matter, closing pages and wiring sheets, including the T25 appendix within the F25C/T25C manual and one additional F25X closing page.

Power-Unit, Gearcase and Electrical Service

These are selected service topics from the included publications. Further examples include fuel-filter replacement and start-in-gear protection adjustment.

• Power-unit repair: Power-unit removal, timing-belt installation, camshaft and valve work, oil-pump inspection, and crankshaft, piston and bearing checks.

• Fuel-system service: Fuel-pump disassembly and step-by-step carburetor overhaul procedures, including float, needle-valve and jet inspection.

• Lower-unit overhaul: Water-pump and shift-rod service, propeller-shaft housing disassembly, drive-shaft work, gear shimming and backlash measurement.

• Brackets and tilt: Upper-case and oil-pan service, steering-arm and clamp-bracket removal, ED/ER shock-absorber checks, and ET/TR power trim and tilt procedures.

• Electrical diagnosis: Ignition, starting, charging and enrichment-system tests, wiring diagrams, connector views and symptom-based trouble-analysis charts.

• Maintenance and specifications: Periodic inspection schedules, valve-clearance adjustment, PTT hydraulic bleeding, torque tables, lubrication data and component wear limits.

The service manuals were written primarily for Yamaha dealers and trained mechanics who already understand the mechanical and electrical principles involved in the work.

Engine Inspection and Carburetor Repair

The engine sections extend beyond assembly drawings to valve-guide replacement, valve-seat refacing, crankshaft inspection and main-bearing and connecting-rod oil-clearance measurements. Exploded views and job instruction charts identify parts, service points and assembly relationships.

The crankshaft inspection cautions explain how incorrect bearing positions can produce misleading clearance measurements and lead to engine damage. Carburetor service also addresses a specific damage risk: steel-wire cleaning can enlarge the jets and affect performance.

For T25Y lubrication, the tables distinguish 10W-30, 10W-40 and 20W-40 four-stroke engine oil from SAE #90 (API GL-4) hypoid gear oil for the lower unit. General torque tables cover M5–M16 fasteners in Nm, m•kgf and ft-lb, alongside component-specific tightening specifications.

Gearcase Shimming and Bracket Work

Separate shimming sections cover USA/Canada and worldwide measuring methods. They distinguish reassembly with the original components from work involving a replacement case or internal parts, and explain how the lower-case P and F deviation marks enter the shim calculations.

This separation helps match the measuring setup and shim selection to the gearcase being serviced. Tool references include the YB-06265/90890-06706 backlash indicator and the associated dial-gauge setup.

Bracket coverage distinguishes the ED/ER shock absorber from the ET/TR power trim and tilt unit. The base manuals also cover internal PTT components, including the tilt cylinder, pump housing, gear pump and motor.

Observe standard workshop safety precautions, use appropriate protection when handling marine fluids, and secure a raised outboard during bracket work.

Wiring Diagrams and Enrichment Tests

The T25Y wiring sheets are labeled FT25BED/T25ER and FT25BET/T25TR, with component references, connectors and wire-color legends. Separate Starting System, Charging System, Enrichment Control System and Power Trim and Tilt Control System diagrams support circuit-specific fault tracing.

Peak-voltage checks cover the charge coil, pulser coil, CDI unit, lighting coil and rectifier/regulator. Enrichment diagnosis includes power-coil tests and a 12-V powered projection test for the electrothermal ram, providing a component check when investigating starting-enrichment faults.

Cold Valve Clearances and Gear-Backlash Examples

For the T25Y variants, the cold valve-clearance specifications are 0.2 ± 0.05 mm at the intake and 0.3 ± 0.05 mm at the exhaust.

The T25Y lower-unit section specifies forward-gear backlash of 0.10–0.30 mm and reverse-gear backlash of 0.40–0.60 mm. These values accompany the separate measuring and shim-adjustment procedures for the two gears.