Yamaha 25C Owner's Manual

Printed in JapanMarch 2003-1.0 × 1 !6L2-28199-1K(25NMH)(E)Printed on recycled paper25COWNER’S MANUALU.S.A.EditionLIT-18626-05-426L2-9-1K Hyoshi 2/14/

E1-5EMB30010IMPORTANT LABELSWARNING LABELS12202023qwWARNINGThis engine is equipped with a neutral starting device. The engine will not start unless th

6-1EEMP10010INDEXAAdjusting trim angle...3-23Air vent screw...2-3BBasic boating rul

6-2EPPeriodic maintenance...4-7Pre-operation checks ...3-10Propeller checking point ...

EMU01599IMPORTANT WARRANTY INFORMATION FOR U.S.A. ANDCANADAWelcome to the Yamaha Family!Congratulations on the purchase of your new Yamaha marine powe

5. Your warranty applies specifically to repairs made in the country of purchase. If yourU.S.-purchased Yamaha needs warranty service while in Canada,

EMU00912*YAMAHA MOTOR CORPORATION, U.S.A.OUTBOARD MOTOR TWO YEAR LIMITED WARRANTYYamaha Motor Corporation, U.S.A. is proud of its heritage and reputat

SPECIFIC PARTS EXCLUDED FROM WARRANTY. Parts replaced due to normal wear or routine maintenance such as oil, spark plugs,shear pins, propellers, hubs,

CUSTOMER SERVICEIf your machine requires warranty service, you must take it to any authorized Yamaha outboard dealer within the continental UnitedStat

EMU01178IMPORTANT WARRANTY INFORMATIONIF YOU USE YOUR YAMAHA OUTSIDE U.S.A. OR CANADAWelcome to the Yamaha Family!Congratulations on the purchase of y

Printed in JapanMarch 2003-1.0 × 1 !6L2-28199-1K(25NMH)(E)Printed on recycled paper25COWNER’S MANUALU.S.A.EditionLIT-18626-05-426L2-9-1K Hyoshi 2/14/

YAMAHA MOTOR CO., LTD.MADE IN JAPANPAYS D'ORIGINE JAPONOUTBOARD MOTOR WARRANTY REGISTRATIONENREGISTREMENT DE LA GARANTIE DU MOTEUR HORS-BORDPleas

E1-6EMB40010BASIC BOATING RULES(Rules of the road)Just as there are rules which apply whenyou are driving on streets and high ways,there are waterway

PLACEPOSTAGEHEREATTN: WARRANTY DEPARTMENTWarranty card 2/27/02 11:47 AM Page 2

ERULES WHEN ENCOUNTERING VESSELSThere are three main situations which youmay encounter with other vessels whichcould lead to a collision unless the St

1-8the other vessel is expected to maintainits course and speed. You must stay outof its way until you are clear of it. Like-wise, if another vessel i

1-9tion. These markers are white with blackletters and orange boarders. They signifyspeed zones, restricted areas, dangerareas, and general informatio

1-10EEMU00016FUELING INSTRUCTIONSwGASOLINE AND ITS VAPORS ARE HIGH-LY FLAMMABLE AND EXPLOSIVE!8 Do not smoke when refueling, andkeep away from sparks,

1-11EEMU00858ENGINE OILIf the recommended engine oil is notavailable, another 2-stroke engine oil witha NMMA-certified TC-W3 rating may beused.EMU0002

1-12EEMU01395PROPELLER SELECTIONThe performance of your outboard motorwill be critically affected by your choice ofpropeller, as an incorrect choice c

1-13EEMU01209START-IN-GEAR PROTECTIONYamaha outboard motors or Yamahaapproved remote control units areequipped with start-in-gear protectiondevice(s).

EMC00010Chapter 2BASIC COMPONENTSMAIN COMPONENTS...2-1OPERATIONS OF CONTROLS AND OTHER FUNCTIONS ...

6L2-9-1K Hyoshi 2/14/03 17:25 Page 2

E2-1EMU01206MAIN COMPONENTS101061!1!0!6!2!4 uiqrwtye!3o!51 Recoil starter handle2 Choke knob3 Warning lamp 4 Gear shift lever5 Throttle-control grip/T

2-2EEMU01206MAIN COMPONENTS12346890q7wuiertyop51 Recoil starter handle2 Gear shift lever3 Tiller handle4 Tilt lock lever5 Shallow water lever6 Transom

2-3Eqwer902051406015qweEMC20010OPERATIONS OF CONTROLSAND OTHER FUNCTIONSEMC21012FUEL TANKIf your model was equipped with aportable fuel tank, its func

2-4EEMC28111ENGINE STOP LANYARD SWITCH(for Tiller control model)The lock-plate on the end of the lanyardmust be attached to the engine stopswitch for

2-5EMC27011ENGINE STOP BUTTON(for Tiller control model)Pushing this button opens the ignition cir-cuit and stops the engine.EMU00062TILLER HANDLE (for

2-6E502011EMU01293Throttle friction adjusting screw/ knobA friction device in the tiller handle pro-vide resistance to movement of the throt-tle grip.

2-7EEMD00011STEERING FRICTION ADJUSTINGSCREW(for Tiller control model)A friction device provides resistance tosteering movement. This is adjustable fo

2-8EEMU00113TRIM TABThe trim tab should be adjusted so thatthe steering control can be turned toeither the right or left by applying thesame amount of

2-9EEMD08010SHALLOW WATER LEVER (If equipped)25Lifting this lever will tilt the motor up par-tially to provide more clearance whenoperating in shallow

2-10EEMD62010TOP COWLING LOCK LEVERTo remove the engine top cowling, pushthe lock lever downward. Then lift off thecowling. When replacing the cowling

Thank you for choosing a Yamaha out-board motor. This Owner’s manual con-tains information needed for proper oper-ation, maintenance and care. A thoro

2-11EEMD80010WARNING SYSTEMcCDo not continue to operate the engine ifthe warning device has activated. Consultyour Yamaha dealer if the problem can-no

2-12E213023q30301430EMU00172OIL LEVEL WARNING / OIL FILTERCLOGGING WARNINGThis engine has an oil level warning sys-tem. If oil level falls below lower

2-13EOil level warning system30The various oil-level warning system functions are as follows:Oil level warning indicator lamp(Bottom cowling)RemarksEn

EMF00010Chapter 3OPERATIONINSTALLATION ...3-1Mounting the outboard motor...3-2Clamping the outboard moto

3-1EEMF10010INSTALLATIONcCIncorrect engine height or obstructions tosmooth water flow (such as the design orcondition of the boat or accessories sucha

3-2EMU00176MOUNTING THE OUTBOARDMOTORwImproper mounting of the outboardmotor could result in hazardous condi-tions such as poor handling, loss of con-

3-3wOverpowering a boat may cause severeinstability. Do not install an outboardmotor with more horsepower than themaximum rating on the capacity plate

3-4EMF14010CLAMPING THE OUTBOARD MOTOR1) Place the outboard on the transom sothat it is positioned as close to thecenter as possible. Tighten the tran

3-5EEMF30010FILLING FUEL AND ENGINE OILFILLING FUEL1) Remove the fuel tank cap.2) Fill the fuel tank carefully.3) Close the cap securely after refueli

3-6EWhile many additives available mayreduce deposits, Yamaha recommendsthe use of Ring Free Fuel Additive, avail-able from your Yamaha dealer. Ring F

GENERAL INFORMATIONBASIC COMPONENTSOPERATIONMAINTENANCETROUBLE RECOVERYINDEXEMA20010CONTENTSREAD THIS OWNER’S MANUAL CAREFULLYBEFORE OPERATING YOUR OU

3-7EEMU00192Procedure1) Remove the top cowling.2) Open the oil tank filler cap by pullingthe tab.3) Slowly fill the engine oil into theengine oil tank

3-8EEMF35011GASOLINE (PETROL) AND OILMIXINGPre-mix model1) Pour oil and gasoline into the fueltank, in that order.1 Engione oil2 Gasoline (Petrol)2) T

3-9EMixing ratio25 : 1Gasoline (Petrol)Engine oil0.04 L 0.48 L 0.56 L 0.96 L(0.04 US qt, (0.51 US qt, (0.59 US qt, (1.01 US qt,0.04 Imp qt) 0.42 Imp q

3-10EMU00204PRE-OPERATION CHECKSwIf any item in the pre-operation check isnot working properly, have it inspectedand repaired before operating the out

3-11E203024OIL3030EMU00210Engine8 Check the engine and engine mounting.8 Look for loose or damaged fasteners.8 Check the propeller for damage.EMU01790

EMU002253-12EEMU01781BREAKING IN ENGINEYour new engine requires a period ofbreak-in to allow mating surfaces of mov-ing parts to wear in evenly. Corre

3-13EEMU01786Break-in procedureRun the engine under load (in gear with apropeller installed) as follows.1) First 10 minutes:Run the engine at the lowe

3-14EEMU01147STARTING ENGINEw8 Before starting the engine, make surethat the boat is tightly moored and thatyou can steer clear of any obstructions.Be

3-15E1) If there is an air vent screw on the fueltank cap, loosen it 2 or 3 turns.90205325-3/30304024*00167190206125N4060123) Squeeze the primer bulb

3-16E5) Attach the engine stop switch lanyardto a secure place on your clothing, oryour arm or leg. Then, install the lockplate on the other end of th

123456EMB00010Chapter 1GENERAL INFORMATIONIDENTIFICATION NUMBERS RECORD ..1-1Outboard motor serial number...1-1EMISSION CONTROL INFORMATION...

3-17E8) Pull the starter handle slowly untilyou feel resistance. Then, give astrong pull straight out to crank andstart the engine. Repeat it, if nece

3-18E309012EMG00010WARMING UP ENGINE1) Before beginning operation, allow theengine to warm up at idling speed for3 minutes. (Failure to do this willsh

3-19EEMU00261SHIFTINGwBefore shifting, make sure there are noswimmers or obstacles in the water nearyou.cCTo change the shifting position from for-war

3-20EEMU00268REVERSEwWhen operating in Reverse, go slowly. Donot open the throttle more than half. Oth-erwise, the boat may become unstable,which coul

3-21EEMG38010STOPPING ENGINELet it cool off for a few minutes at idle orlow speed first. Stopping the engineimmediately after operating at high speedi

3-22E000910qEMU01412TRIMMING OUTBOARDMOTORThe trim angle of the outboard motorhelps determine the position of the bowof the boat in the water. The cor

3-23E001770q404015*q2525-3/30ADJUSTING TRIM ANGLEEMU00951Manual tilt modelThere are 4 or 5 holes provided in theclamp bracket to adjust the outboardmo

3-24E001672q001673w001674eEMU19160Trim angle settings and boat handlingWhen the boat is on plane, a bow-up atti-tude results in less drag, greater sta

3-25ENOTE:Depending on the type of boat, the out-board motor trim angle may have littleeffect on the trim of the boat when oper-ating.EMG70011CRUISING

3-26E402061**25EMG71310PROCEDURE251) Place the gear shift lever in the neu-tral position.2) Push the tilt lock lever down torelease.402072*25-3/302540

E1-1EMU00005IDENTIFICATION NUMBERSRECORDEMU00007OUTBOARD MOTOR SERIAL NUM-BERThe outboard motor serial number isstamped on the label attached to the p

3-27EEMH10110TILTING UP/DOWNIf the engine will be stopped for sometime, or if the boat is moored in shallows,the engine should be tilted up to protect

3-28EEMG63910PROCEDURE FOR TILTING UP251) Place the gear shift lever in Neutral.2) Remove the fuel line connection fromthe motor.N406012402061**402075

3-29E402035403024402075*EMG73410PROCEDURE FOR TILTING DOWN251) Return the shallow water lever.2) Slightly tilt up the engine until the tiltsupport bar

3-30E403036EMH60010CRUISING IN OTHERCONDITIONSCRUISING IN SALT WATERAfter operating in salt water, wash out thecooling-water passages with fresh water

E-MEMO- 6L2-9-1K-3 2/17/03 18:40 Page 32

EMK00010Chapter 4MAINTENANCESPECIFICATIONS ...4-1TRANSPORTING AND STORINGOUTBOARD MOTOR ...

4-1EEMK10011*SPECIFICATIONSModelUnit 25MHCItem25 (2.5, 18)35 (3.5, 25)8Spark plug N·m (kgf·m, lb·ft)8Propeller nut N·m (kgf·m, lb·ft)DIMENSIONSPERFORM

4-2EEMU01369*TRANSPORTING ANDSTORING OUTBOARD MOTORwLeaking fuel is a fire hazard. When trans-porting and storing the outboard motor,close the air ven

4-3EWhen transporting or storing the out-board motor while removed from a boat,fold the tiller handle and lean the motoron the tiller handle to keep i

4-4EEMK21010Filling Fuel TankFill the fuel tank with fresh fuel and addone ounce of “Yamaha Fuel Conditionerand Stabilizer” (Part No. LUB-FUELC-12-00)

E1-212108021121080222525-3/30EMU01385EMISSION CONTROLINFORMATIONEMU01386NORTH AMERICAN MODELSThis engine conforms to U.S. Environ-mental Protection Ag

4-5EEMK22211Flushing Cooling System and FoggingEngineCooling system flushing is essential toprevent the cooling system from cloggingup with salt, sand

4-6EEMK26111Lubrication1) Remove the spark plugs, and spray a10 second spray of “Yamaha Stor-Rite Engine Fogging Oil” into eachcylinder. Grease the s

4-7EEMK33011REPLACEMENT PARTSIf replacement parts are necessary, useonly genuine Yamaha parts or equiva-lents of the same type and of equivalentstreng

4-8EEMU19460MAINTENANCE CHARTFrequency of maintenance operations may be adjusted according to the operating con-ditions, but the following table gives

4-9EEMU01202CLEANING AND ADJUSTING SPARKPLUGwWhen removing or installing a spark plug,be careful not to damage the insulator. Adamaged insulator could

4-10EWhen fitting the plug, always clean thegasket surface and use a new gasket.Wipe off any dirt from the threads andscrew in the spark plug to the c

4-11EEMK38010CHECKING FUEL SYSTEMwGasoline (petrol) and its vapors are highlyflammable and explosive. Keep awayfrom sparks, cigarettes, flames or othe

4-12EEMU00370INSPECTING FUEL FILTERwGasoline (petrol) is highly flammable, andits vapors are flammable and explosive.8 If you have any question about

4-13E5) Attach the filter assembly to thebracket so that the fuel hoses areattached to the filter assembly.6) Run the engine and check the filterand l

4-14E2) Verify whether the idle speed is set tospecification. For idle speed specifica-tions, see “Specifications” in thischapter.NOTE:Correct idling

E1-38 This product emits exhaust gases whichcontain carbon monoxide, a colorless,odorless gas which may cause braindamage or death when inhaled. Symp-

4-15EEMK78010CHECKING WIRING ANDCONNECTORS1) Check that each grounding wire isproperly secured.2) Check that each connector is engagedsecurely.EXHAUST

4-16EMU00366GREASINGYamaha marine grease(Water resistant grease)25103141b 6L2-9-1K-4 2/25/03 15:51 Page 17

4-17E25-3/30103141aEMU00366GREASINGYamaha marine grease(Water resistant grease) 6L2-9-1K-4 2/25/03 15:51 Page 18

4-18EEMU00388CHECKING PROPELLERwYou could be seriously injured if theengine accidentally starts while you arenear the propeller.8 Before inspecting, r

4-19EEMU00397Installing the PropellercC8 Be sure to install the thrust washerbefore installing propeller, otherwise,lower case and propeller boss may

4-20E000650qwEMU01773CHANGING GEAR OILw8 Be sure the outboard motor is securelyfastened to the transom or a stablestand. You could be severely injured

4-21ENOTE:For disposal of used oil consult yourYamaha dealer.5) With the outboard motor in a verticalposition, and using a flexible or pres-surized fi

4-22E603023902054To clean the fuel tank1) Empty the fuel tank into an approvedgasoline (petrol) container.2) Pour a small amount of suitable sol-vent

4-23E001183102025EMU00409MOTOR EXTERIOREMU00410Cleaning the Outboard MotorAfter use, wash the exterior of the out-board with fresh water.Flush the coo

EMN00010Chapter 5TROUBLE RECOVERYTROUBLESHOOTING ...5-1TEMPORARY ACTION IN EMERGENCY ...

E1-48 When a swimmer is in the water nearyou shift into neutral and shut off theengine.8 Be informed about boating safety. Addi-tional publications an

5-1EEMU01204¯TROUBLESHOOTINGA problem in the fuel, compression, or ignition systems can cause poor starting, loss ofpower, or other problems. The trou

5-2EB. Engine idlesirregularly or stalls.Trouble Possible Cause Remedy1. Spark plug(s) fouled or incorrecttype.2. Fuel system obstructed.3. Fuel conta

5-3EC. Warning buzzersounds orindicator lamplights.Trouble Possible Cause Remedy1. Cooling system clogged.2. Engine oil level low.3. Heat range of spa

5-4ETrouble Possible Cause Remedy13. Poor connections or damagedignition wiring.14. Failed ignition parts.15. Specified engine oil not used.16. Thermo

5-5E607011EMN20010TEMPORARY ACTION INEMERGENCYEMU01492IMPACT DAMAGEwThe outboard motor can be seriouslydamaged by a collision while operatingor traile

5-6EMU00423STARTER WILL NOT OPERATEIf the starter mechanism does not operate(engine cannot be cranked with thestarter), the engine can be started with

5-7EMU00950Emergency Starting Engine1) Remove the top cowling.2) Remove the start-in-gear protectioncable from the starter if equipped it.3) Remove th

5-8EMN50011TREATMENT OF SUBMERGEDMOTORIf the outboard motor is submerged,immediately take it a Yamaha dealer. Oth-erwise, some corrosion may begin alm

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EMP00010Chapter 6INDEXINDEX..............6-1123456E 6L2-9-1K-6 2/25/03 15:52 Page 1