Yamaha F25A Service Manual

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65W-28197-Z8-C2

290362

SERVICE MANUAL

MANUEL D’ENTRETIEN

WARTUNGSHANDBUCH

MANUAL DE SERVICIO

E

F

D

ES

F20A, F25A

WORLD WIDE

USA, CANADA

F25X

Table of Contents

Other manuals for Yamaha F25A

Owner's Manual232 pages

Questions and Answers:

B
Brian BernardAug 14, 2025
What to do if my Yamaha Outboard Motor engine will not start?
- E
  Emily PenaAug 14, 2025
  If your Yamaha Outboard Motor engine won't start but the starter is operating, several factors could be at play. First, ensure the fuel tank isn't empty and that you're using clean, fresh fuel. A clogged fuel filter could also be the culprit, so try cleaning or replacing it. Make sure you are following the correct starting procedure. Other potential issues include fouled or incorrect spark plugs (inspect, clean, or replace them), incorrectly fitted spark plug caps (check and refit), poor ignition wiring connections (check for wear, tighten, or replace wires), a missing engine stop switch lanyard (attach it), or damaged internal engine parts or fuel pump malfunctions, which would require servicing by a Yamaha dealer.
B
Brenda YoungAug 17, 2025
Why is the warning buzzer sounding on my Yamaha F25A Outboard Motor?
- N
  Norman SmithAug 18, 2025
  If the warning buzzer sounds or the indicator lamp lights on your Yamaha Outboard Motor, it could be due to several reasons. Check the water intake for any restrictions, as the cooling system might be clogged. Ensure the engine oil level is adequate and that you're using the specified engine oil. Also, the spark plug's heat range might be incorrect, so inspect and replace it if necessary. Other potential causes include contaminated or deteriorated engine oil (replace it), a clogged oil filter, or improperly distributed load on the boat (distribute the load evenly). For issues like a faulty water pump/thermostat or oil feed/injection pump malfunctions, it's best to have it serviced by a Yamaha dealer.
J
John SalasAug 25, 2025
How to fix a Yamaha Outboard Motor when the starter will not operate?
- D
  david75Aug 25, 2025
  If your Yamaha Outboard Motor's starter won't operate, begin by checking the battery condition and ensuring it has the recommended capacity. Weak or low battery capacity can prevent the starter from functioning. Next, inspect the battery connections for looseness or corrosion; tighten the cables and clean the terminals if needed. Also, verify if the fuse for the electric start circuit is blown and replace it with the correct amperage after identifying and fixing the cause of the overload. Ensure the shift lever is in neutral. If these steps don't resolve the issue, the starter components may be faulty, requiring service by a Yamaha dealer.
B
Beth JohnsonSep 6, 2025
What causes a Yamaha F25A to vibrate excessively?
- J
  Jacqueline LopezSep 6, 2025
  Excessive vibration in your Yamaha Outboard Motor can be caused by a damaged propeller, which should be repaired or replaced. Alternatively, the propeller shaft could be damaged, requiring service by a Yamaha dealer. Check for weeds or foreign matter tangled on the propeller and remove them. Ensure the motor mounting bolts are tightened. If the steering pivot is loose or damaged, tighten it or have it serviced by a Yamaha dealer.
A
Austin HouseSep 10, 2025
How to fix Yamaha F25A when the starter will not operate?
- N
  Nicole StanleySep 12, 2025
  If the starter of your Yamaha Outboard Motor isn't working, here are some things to check: * A weak or low battery capacity could be the cause. Inspect the battery condition and use a battery with the recommended capacity. * Loose or corroded battery connections. Tighten the battery cables and clean the terminals. * Blown fuse for the electric start circuit. Find the cause of the electric overload and repair it, then replace the fuse with one of the correct amperage. * Engine stop switch lanyard not attached. Attach the lanyard. * Shift lever in gear. Shift to neutral.

Yamaha F25A Specifications

General

Fuel Induction System	EFI (Electronic Fuel Injection)
Full Throttle RPM Range	5000 - 6000 rpm
Exhaust	Through Propeller Hub
Cooling System	Water-cooled
Displacement	498 cc
Maximum Output	25 hp at 5500 rpm
Starting System	Electric
Alternator Output	12V 16A
Recommended Fuel	Unleaded gasoline
Ignition System	TCI
Gear Shift	Forward, Neutral, Reverse
Steering	Tiller
Trim Method	Manual
Fuel Tank Capacity	Varies (Separate Tank)
Recommended Engine Oil	Yamalube 4-Stroke Outboard Oil (10W-30)

Summary

SAFETY WHILE WORKING

FIRE PREVENTION

Guidelines for safely handling flammable gasoline and preventing fires.

VENTILATION

Importance of proper ventilation for hazardous petroleum vapors and exhaust gases.

SELF-PROTECTION

CHAPTER 2 SPECIFICATIONS

GENERAL SPECIFICATIONS

Overall specifications including dimensions, weight, performance, and power unit details.

MAINTENANCE SPECIFICATIONS

Specific maintenance data for engine, lower unit, and electrical systems.

TIGHTENING TORQUES

Torque specifications for various parts and assemblies.

CHAPTER 3 PERIODIC INSPECTION AND ADJUSTMENT

MAINTENANCE INTERVAL CHART

Provides a schedule for routine maintenance tasks based on operating hours and time intervals.

CHAPTER 5 POWER UNIT

FLYWHEEL MAGNETO

RECOIL STARTER

STATOR AND TIMING BELT

ELECTRICAL UNIT

CONTROL UNIT

CYLINDER HEAD AND OIL PUMP

Exploded view and removal/installation chart for cylinder head and oil pump components.

OIL PUMP

Exploded diagram, removal/installation chart, and service points for the oil pump.

CHAPTER 6 LOWER UNIT

LOWER UNIT

General information and procedures for the lower unit.

WATER PUMP

PROPELLER SHAFT ASSY.

PROPELLER SHAFT HOUSING ASSY.

FORWARD GEAR AND DRIVE SHAFT

Exploded diagram, removal/installation, and service points for forward gear and drive shaft.

CHAPTER 7 BRACKET UNIT

STEERING HANDLE

STEERING FRICTION (MH, EH-option)

UPPER CASE ASSY.

STEERING BRACKET

POWER TRIM AND TILT (PTT) UNIT

Exploded view and removal/installation procedures for the power trim and tilt unit.

CLAMP BRACKET (MH, EH, E)

CLAMP BRACKET (EHT, ET)

CHAPTER 8 ELECTRICAL SYSTEM

ELECTRICAL COMPONENTS

WIRE HARNESS (MH)

WIRE HARNESS (EH)

WIRE HARNESS (EHT)

WIRE HARNESS (E)

WIRE HARNESS (ET)

ELECTRICAL ANALYSIS

Inspection procedures using digital circuit testers, peak voltage measurement, and test harnesses.

IGNITION SYSTEM

Details on ignition spark gap, peak voltage, spark plugs, and engine stop switch.

IGNITION CONTROL SYSTEM

Information on pulser coil, oil pressure switch, engine temperature sensor, and warning lamp.

STARTING SYSTEM

CHARGING SYSTEM

POWER TRIM AND TILT (PTT) CONTROL SYSTEM (EHT)

POWER TRIM AND TILT (PTT) CONTROL SYSTEM (ET)

CHAPTER 9 TROUBLE-ANALYSIS

TROUBLE-ANALYSIS

Guide to identifying and diagnosing engine problems and their common causes.

TROUBLE-ANALYSIS

ENGINE WILL NOT START

Troubleshooting steps when the engine fails to start.

ROUGH IDLING

Troubleshooting steps for rough or unstable engine idling.

ENGINE STALLS

Troubleshooting steps when the engine stops unexpectedly.

ENGINE WILL NOT STOP

Troubleshooting steps when the engine does not shut off.

POOR PERFORMANCE

Troubleshooting steps for reduced engine performance or power.

OVERHEATING

Troubleshooting steps for engine overheating issues.

TILT MOTOR WILL NOT RUN

POOR BATTERY CHARGING

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