- DL manuals
- Yamaha
- Outboard Motor
- 4AC
- Owner's Manual
Yamaha 4AC Owner's Manual
Summary of 4AC
Page 1
Read this manual carefully before operating this outboard motor. Owner’s manual 4ac 5c 6e0-28199-28-e0 u6e028e0.Book page 1 tuesday, february 10, 2009 3:19 pm.
Page 2
Read this manual carefully before operating this outboard motor. Keep this manual onboard in a waterproof bag when boating. This manual should stay with the outboard motor if it is sold. U6e028e0.Book page 1 tuesday, february 10, 2009 3:19 pm.
Page 3
Important manual information emu25105 to the owner thank you for choosing a yamaha outboard motor. This owner’s manual contains infor- mation needed for proper operation, mainte- nance and care. A thorough understanding of these simple instructions will help you obtain maximum enjoyment from your ne...
Page 4: Table Of Contents
Table of contents safety information............................. 1 outboard motor safety .................... 1 propeller ............................................. 1 rotating parts ..................................... 1 hot parts............................................. 1 electric shock .....
Page 5: Table Of Contents
Table of contents remove cowling ............................... 25 fuel system ...................................... 25 controls ............................................ 25 engine shut-off cord (lanyard) .......... 25 oil ..................................................... 25 engine ...........
Page 6: Safety Information
1 safety information emu33622 outboard motor safety observe these precautions at all times. Emu36501 propeller people can be injured or killed if they come in contact with the propeller. The propeller can keep moving even when the motor is in neu- tral, and sharp edges of the propeller can cut even ...
Page 7: Safety Information
Safety information 2 emu33780 modifications do not attempt to modify this outboard motor. Modifications to your outboard motor may re- duce safety and reliability, and render the out- board unsafe or illegal to use. Emu33740 boating safety this section includes a few of the many im- portant safety p...
Page 8: Safety Information
Safety information 3 ● avoid sharp turns or other maneuvers that make it hard for others to avoid you or un- derstand where you are going. ● avoid areas with submerged objects or shallow water. ● ride within your limits and avoid aggressive maneuvers to reduce the risk of loss of con- trol, ejection...
Page 9: General Information
General information 4 emu25171 identification numbers record emu25183 outboard motor serial number the outboard motor serial number is stamped on the label attached to the port side of the clamp bracket. Record your outboard motor serial number in the spaces provided to assist you in ordering spare ...
Page 10: General Information
General information 5 1. C-tick label location zmu01697 u6e028e0.Book page 5 tuesday, february 10, 2009 3:19 pm.
Page 11: General Information
General information 6 emu33520 read manuals and labels before operating or working on this motor: ● read this manual. ● read any manuals supplied with the boat. ● read all labels on the outboard motor and the boat. If you need any additional information, contact your yamaha dealer. Emu33831 warning ...
Page 12: General Information
General information 7 emu35281 contents of labels the above warning labels mean as follows. 1 warning ewm01691 emergency starting does not have start- in-gear protection. Ensure shift control is in neutral before starting engine. 2 warning ewm01681 ● keep hands, hair, and clothing away from rotating...
Page 13: General Information
General information 8 4 warning ewm01701 gasoline is highly flammable and explo- sive. Shut off engine before refueling. Tighten tank cap and air vent screw when not in use. Emu33843 symbols the following symbols mean as follows. Notice/warning read owner’s manual hazard caused by continuous rotatio...
Page 14: General Information
General information 9 engine start/ engine cranking zmu05668 u6e028e0.Book page 9 tuesday, february 10, 2009 3:19 pm.
Page 15
Specifications and requirements 10 emu31480 specifications tip: “(al)” stated in the specification data below represents the numerical value for the alumi- num propeller installed. Likewise, “(sus)” represents the value for stainless steel propeller installed and “(pl)” for plastic propeller install...
Page 16
Specifications and requirements 11 regular gasoline: 100 :1 lubrication: pre-mixed fuel and oil recommended gear oil: hypoid gear oil sae#90 gear oil quantity: 0.100 l (0.106 us qt, 0.088 imp.Qt) tightening torque for engine: spark plug: 25.0 nm (2.55 kgf-m, 18.4 ft-lb) noise and vibration level: op...
Page 17
Specifications and requirements 12 your yamaha dealer can help you select the right propeller for your boating needs. Select a propeller that will allow the engine to reach the middle or upper half of the operating range at full throttle with the maximum boat- load. Generally, chose a larger pitch p...
Page 18
Specifications and requirements 13 does not recommend gasohol containing methanol because it can cause fuel system damage or engine performance problems. Emu36880 muddy or acidic water yamaha strongly recommends that you have your dealer install the optional chromium-plat- ed water pump kit if you u...
Page 19: Components
Components 14 emu2579m components diagram tip: * may not be exactly as shown; also may not be included as standard equipment on all models. 4ac 1. Air vent screw 2. Fuel tank cap 3. Top cowling 4. Cowling lock lever 5. Steering friction adjuster 6. Anti-cavitation plate 7. Propeller 8. Cooling water...
Page 20: Components
Components 15 5c emu25802 fuel tank if your model was equipped with a portable fuel tank, its function is as follows. Warning ewm00020 the fuel tank supplied with this engine is its dedicated fuel reservoir and must not be used as a fuel storage container. Com- mercial users should conform to releva...
Page 21: Components
Components 16 emu25821 fuel tank if your model included a fuel tank, its parts and functions are as follows. Emu25830 fuel joint this joint is used to connect the fuel line. Emu25841 fuel gauge this gauge is located on either the fuel tank cap or on the fuel joint base. It shows the ap- proximate am...
Page 22: Components
Components 17 emu25891 open with the lever/knob in this position, fuel flows to the carburetor. Normal running is done with the lever/knob in this position. Emu25901 open the fuel cock has two open positions, one for selecting fuel flow from the built-in fuel tank, and one for an external tank. Fuel...
Page 23: Components
Components 18 emu25941 throttle grip the throttle grip is on the tiller handle. Turn the grip counterclockwise to increase speed and clockwise to decrease speed. Emu25961 throttle indicator the fuel consumption curve on the throttle in- dicator shows the relative amount of fuel con- sumed for each t...
Page 24: Components
Components 19 emu25993 engine shut-off cord (lanyard) and clip the clip must be attached to the engine shut- off switch for the engine to run. The cord should be attached to a secure place on the operator’s clothing, or arm or leg. Should the operator fall overboard or leave the helm, the cord will ...
Page 25: Components
Components 20 emu26122 steering friction adjuster a friction device provides adjustable resis- tance to the steering mechanism, and can be set according to operator preference. An ad- justing screw or bolt is located on the swivel bracket. To increase resistance, turn the adjuster clockwise. To decr...
Page 26: Installation
Installation 21 emu26902 installation the information presented in this section is in- tended as reference only. It is not possible to provide complete instructions for every possi- ble boat and motor combination. Proper mounting depends in part on experience and the specific boat and motor combinat...
Page 27: Installation
Installation 22 notice ecm01631 ● check that the idle hole stays high enough to keep out water getting inside engine even if the boat is in stationary with maximum load. ● incorrect engine height or obstructions to the smooth flow of water (such as the design or condition of the boat, or ac- cessori...
Page 28: Installation
Installation 23 packaging. If used, they must be of at least the same quality of material and strength and must be tightened se- curely. After tightening, test run the engine and check their tightness. [ewm00651] u6e028e0.Book page 23 tuesday, february 10, 2009 3:19 pm.
Page 29: Operation
Operation 24 emu36381 first-time operation emu30174 breaking in engine your new engine requires a period of break-in to allow mating surfaces of moving parts to wear in evenly. Correct break-in will help en- sure proper performance and longer engine life. Notice: failure to follow the break-in proce...
Page 30: Operation
Operation 25 notice ecm00120 do not start the engine out of water. Over- heating and serious engine damage can occur. Emu37141 fuel level be sure you have plenty of fuel for your trip. A good rule is to use 1/3 of your fuel to get to the destination, 1/3 to return, and to keep 1/3 as an emergency re...
Page 31: Operation
Operation 26 emu27141 engine ● check the engine and engine mounting. ● look for loose or damaged fasteners. ● check the propeller for damage. Emu36953 install cowling 1. Be sure that a cowling lock lever is re- leased. 2. Be sure that the rubber seal is seated all the way around the top cowling. 3. ...
Page 32: Operation
Operation 27 3. Remove the portable tank from the boat. 4. Be sure you are in a well-ventilated out- door area, either securely moored or trail- ered. 5. Do not smoke and keep away from sparks, flames, static electric discharge, or other sources of ignition. 6. If you use a portable container to sto...
Page 33: Operation
Operation 28 3. Remove the portable tank from the boat. 4. Be sure you are in a well-ventilated out- door area, either securely moored or trail- ered. 5. Do not smoke and keep away from sparks, flames, static electric discharge, or other sources of ignition. 6. If you use a portable container to sto...
Page 34: Operation
Operation 29 if equipped with a portable fuel tank 1. Pour oil into the portable fuel tank, and then add gasoline. 2. Replace the fuel tank cap and close tight- ly. 3. Shake the fuel tank to mix the fuel thor- oughly. 4. Make sure that the oil and gasoline are mixed. If equipped with a built-in fuel...
Page 35: Operation
Operation 30 emu27451 operating engine emu27466 sending fuel (portable tank) warning ewm00420 ● before starting the engine, make sure that the boat is tightly moored and that you can steer clear of any obstructions. Be sure there are no swimmers in the water near you. ● when the air vent screw is lo...
Page 36: Operation
Operation 31 emu27474 sending fuel warning ewm00420 ● before starting the engine, make sure that the boat is tightly moored and that you can steer clear of any obstructions. Be sure there are no swimmers in the water near you. ● when the air vent screw is loosened, gasoline vapor will be released. G...
Page 37: Operation
Operation 32 emu27493 starting engine warning ewm01600 before starting the engine, make sure that the boat is tightly moored and that you can steer clear of any obstructions. Be sure there are no swimmers in the water near you. Emu27508 manual start models (tiller control) warning ewm01840 ● failure...
Page 38: Operation
Operation 33 tip: ● it is not necessary to use the choke when starting a warm engine. ● if the choke knob is left in the “ ” (start) position while the engine is running, the en- gine will run poorly or stall. 5. Pull the manual starter handle slowly until you feel resistance. Then give a strong pul...
Page 39: Operation
Operation 34 the cooling water pilot hole is blocked. Consult your yamaha dealer if the prob- lem cannot be located and corrected. Check that no water leaks from the joints be- tween the exhaust cover, cylinder head, and body cylinder. Emu27670 warming up engine emu27683 choke start models after sta...
Page 40: Operation
Operation 35 2. After the engine is at idle speed in gear move the gear shift lever firmly and crisp- ly into the neutral position. Tip: the outboard motor can turn 360° in its brack- et (full-pivot system). The boat can also be backed up by simply turning the outboard mo- tor around 180° with the s...
Page 41: Operation
Operation 36 3. Disconnect the fuel line if you are using an external fuel tank. Tip: if the outboard motor is equipped with an en- gine shut-off cord, the engine can also be stopped by pulling the cord and removing the clip from the engine shut-off switch. Emu27862 trimming outboard motor warning e...
Page 42: Operation
Operation 37 emu27872 adjusting trim angle for manual tilt models there are 4 or 5 holes provided in the clamp bracket to adjust the outboard motor trim an- gle. 1. Stop the engine. 2. Tilt the outboard motor up, and then re- move the trim rod from the clamp bracket. 3. Reposition the rod in the des...
Page 43: Operation
Operation 38 bow down too much trim-in causes the boat to “plow” through the water, decreasing fuel economy and making it hard to increase speed. Operat- ing with excessive trim-in at higher speeds also makes the boat unstable. Resistance at the bow is greatly increased, heightening the danger of “b...
Page 44: Operation
Operation 39 2. Tighten the steering friction adjuster by turning it clockwise to prevent the motor from turning freely. 3. Tighten the air vent screw. 4. Close the fuel cock. 5. Hold the rear of the top cowling or the rear handle (if equipped) with one hand and tilt the outboard motor up fully unti...
Page 45: Operation
Operation 40 emu28033 procedure for tilting down (manual tilt models) 1. Slightly tilt the outboard motor up. 2. If equipped with the tilt support bar: slow- ly tilt the outboard motor down while pull- ing the tilt support bar lever up. 3. If equipped with the tilt support knob: pull the knob out, a...
Page 46: Operation
Operation 41 2. Slightly tilt the outboard motor up until the tilt support bar automatically turns to the lock position to support the engine. The outboard motor is equipped with 2 or 3 positions for shallow water cruising. 3. To lower the outboard motor to the nor- mal running position, first sligh...
Page 47: Maintenance
Maintenance 42 emu28227 transporting and storing out- board motor warning ewm00693 ● use care when transporting fuel tank, whether in a boat or car. ● do not fill fuel container to maximum capacity. Gasoline will expand consider- ably as it warms up and can build up pressure in the fuel container. T...
Page 48: Maintenance
Maintenance 43 notice ecm01411 ● do not place the outboard motor on its side before the cooling water has drained from it completely, otherwise water may enter the cylinder through the exhaust port and cause engine trouble. ● store the outboard motor in a dry, well- ventilated place, not in direct s...
Page 49: Maintenance
Maintenance 44 emu28402 lubrication 1. Install the spark plug(s) and torque to proper specification. For information on spark plug installation, see page 48. 2. Change the gear oil. For instructions, see page 51. Inspect the oil for the presence of water that indicates a leaky seal. Seal replacement...
Page 50: Maintenance
Maintenance 45 ● operating without sufficient time for engine to warm up and cool down ● frequent quick acceleration and decelera- tion ● frequent shifting ● frequently starting and stopping the en- gine(s) ● operation that fluctuates often between light and heavy cargo loads outboard motors operati...
Page 51: Maintenance
Maintenance 46 fuel line(high pres- sure) inspection or replace- ment as necessary fuel line(low pres- sure) inspection fuel line(low pres- sure) inspection or replace- ment as necessary fuel pump inspection or replace- ment as necessary fuel/engine oil leakage inspection gear oil replacement greasi...
Page 52: Maintenance
Maintenance 47 emu34451 maintenance chart 2 emu28941 greasing yamaha grease a (water resistant grease) yamaha grease d (corrosion resistant grease; for propeller shaft) 4ac, 5c item actions every 1000 hours exhaust guide/exhaust manifold inspection or replace- ment as necessary u6e028e0.Book page 47...
Page 53: Maintenance
Maintenance 48 emu28956 cleaning and adjusting spark plug the spark plug is an important engine compo- nent and is easy to inspect. The condition of the spark plug can indicate something about the condition of the engine. For example, if the center electrode porcelain is very white, this could indic...
Page 54: Maintenance
Maintenance 49 emu29043 inspecting idling speed warning ewm00451 ● do not touch or remove electrical parts when starting or during operation. ● keep hands, hair, and clothes away from the flywheel and other rotating parts while the engine is running. Notice ecm00490 this procedure must be performed ...
Page 55: Maintenance
Maintenance 50 ● check the propeller shaft oil seal for dam- age. Emu30662 removing propeller emu29197 spline models 1. Straighten the cotter pin and pull it out us- ing a pair of pliers. 2. Remove the propeller nut, washer, and spacer (if equipped). Warning! Do not use your hand to hold the propell...
Page 56: Maintenance
Maintenance 51 tip: if the propeller nut does not align with the pro- peller shaft hole after tightening it, loosen the nut until it aligns with the hole. Emu29287 changing gear oil warning ewm00800 ● be sure the outboard motor is securely fastened to the transom or a stable stand. You could be seve...
Page 57: Maintenance
Maintenance 52 7. Put a new gasket on the gear oil drain screw. Insert and tighten the gear oil drain screw. Emu29302 cleaning fuel tank warning ewm00920 gasoline is highly flammable, and its va- pors are flammable and explosive. ● if you have any question about properly doing this procedure, consul...
Page 58: Maintenance
Maintenance 53 emu29312 inspecting and replacing anode(s) yamaha outboard motors are protected from corrosion by sacrificial anodes. Inspect the external anodes periodically. Remove scales from the surfaces of the anodes. Consult a yamaha dealer for replacement of external anodes. Notice ecm00720 do...
Page 59: Trouble Recovery
Trouble recovery 54 emu29427 troubleshooting a problem in the fuel, compression, or ignition systems can cause poor starting, loss of pow- er, or other problems. This section describes basic checks and possible remedies, and cov- ers all yamaha outboard motors. Therefore some items may not apply to ...
Page 60: Trouble Recovery
Trouble recovery 55 a. Check for pinched or kinked fuel line or oth- er obstructions in fuel system. Q. Is fuel contaminated or stale? A. Fill tank with clean, fresh fuel. Q. Is fuel filter clogged? A. Clean or replace filter. Q. Have ignition parts failed? A. Have serviced by a yamaha dealer. Q. Ha...
Page 61: Trouble Recovery
Trouble recovery 56 q. Is load on boat improperly distributed? A. Distribute load to place boat on an even plane. Q. Is water pump or thermostat faulty? A. Have serviced by a yamaha dealer. Q. Is there excess water in fuel filter cup? A. Drain filter cup. Engine power loss. Q. Is propeller damaged? ...
Page 62: Trouble Recovery
Trouble recovery 57 a. Connect correctly. Q. Is heat range of spark plug incorrect? A. Inspect spark plug and replace it with rec- ommended type. Q. Is high pressure fuel pump drive belt bro- ken? A. Have serviced by a yamaha dealer. Q. Is engine not responding properly to shift lever position? A. H...
Page 63: Trouble Recovery
Trouble recovery 58 ● do not attach the cord to clothing that could tear loose. Do not route the cord where it could become entangled, pre- venting it from functioning. ● avoid accidentally pulling the cord dur- ing normal operation. Loss of engine power means the loss of most steering control. Also...
Page 64: Trouble Recovery
Trouble recovery 59 emu33501 treatment of submerged motor if the outboard motor is submerged, immedi- ately take it to a yamaha dealer. Otherwise some corrosion may begin almost immediate- ly. Notice: do not attempt to run the out- board motor until it has been completely inspected. [ecm00401] u6e02...
Page 65
U6e028e0.Book page 60 tuesday, february 10, 2009 3:19 pm.
Page 66
Yamaha motor co., ltd. Printed on recycled paper printed in japan march 2009–0.3 × 1 cr u6e028e0.Book page 1 tuesday, february 10, 2009 3:19 pm.