Fuel meter housing Remove the four screws and pull the fuel meter housing out of the fuel tank. If not, fuel may spout out of. Priming pump and fuel joint Hold the fuel hose joint with your hand, insert a slotted-head screwdriver into the band end gap, and loosen the band by prying the band ends.
Push the hose end out of the band with the screwdriver. Cleaning,inspectionand repair Fuel system trouble, in most cases, stems from fuel leakage, a clogged strainer, or a jammed or worn check valve. To check the fuel system,proceed asfollows:.
Primingpump and fuel joints Check the priming pump and fuel hoses for cracks or holes and replace them as required. Also, check the operation of the check valveby blowing into it. Add a small quantity of suitable cleaning solvent to the fuel tank and thorou1. After cleaning, drain off the cleaningsolventcompletely. Fuel meter housing Thoroughly clean the strainer on the end of the suction pipe with suitable cleaning solvent and blow it dry with com-.
NOTE: The check valveson the inlet and outlet sides are of the same type. After checking the check valves, put marks on them so that they can easily be distinguished. Pass the fuel hose through the band, inend of the sert the fuel joint into the hose, and hold the hose with the band. Always use new gasketsto prevent fuel leakage past joints. To prevent the fuel from leaking past the fuel hose joints, replace any fatigued fuel hose bands.
Fuel meter housing Fit the fuel strainer to the end of the suction pipe. Place the gasket on the tank, and place the suction pipe, in the tank, and secure them with screws.
Fuel hose a. Install the check valve outlet on the side in the direction of the arrow of the priming pump and the other one inlet on the opposite side, then secure the valves with bands. Connect the long nose to the check valve inlet , and clamp it with the band. Likewise, connect the short hoseto the check valve outlet , and clamp it with the band. Description: The fuel system from bottom cowling to carburetor consistsof the fuel joint attached to the bottom cowling , fuel filter, and carburetor.
Particularly, the carburetor has a. Gasoline ishighly inflammable and explosive. Avoid smoking while servicing the fuel system. Remove the clip holding the fuel hose from the fuel hose insert fitted to the fuel joint. Remove the fuel hose from the fuel. The fuel filter removes any water or impurities contained in the fuel to keep them from entering the engine,. NOTE: It is advisable to insert a slotted-head screwdriver between the fuel hose and fuel joint and pry out the hosefor easyremoval.
Carburetor This single-barrel type carburetor uses a butterfly throttle valve and incorporates a fuel pump. When starting the engine,. The pump has a diaphragm which is operated by changes in the crankcase pressure, and a check valve is installed in each of the inlet and outlet of the pump. The movement of the diaphragm draws fuel and sends it to the carburetor float chamber.
When air flows through the venturi, a vacuum is produced around it so that the fuel is sprayed into the main bore air horn. The fuel flow changes properly depending on the engine speed. Fuel joint and fuel hoses After cleaning the fuel joint, push the valve pin and blow the fuel joint with compressed air from the fuel hoseside.
Fuel filter Remove the dust and dirt in the fuel strainer with a cleaning agent, and blow the strainer in the opposite direction to the arrow mark on it with compressed air. Removing the fuel strainer Remove the clip holding the hose to each end of the fuel strainer, and remove the fuel hose.
Fuel joint Engine side Bring the fuel joint into the bracket from its front, and screw in the bolt from the lower side. Fuel filter a. Fit one end of the fuel hose over the fuel joint and the other end over the fuel filter, then clip on both ends. Be sure the arrow marked on the filter is on the hose side. It incorporates a diaphragm fuel pump which is operated by crankcase pressure pulses. The throttle valve is interlocked with the throttle grip and controls the engine speed.
Functions of the carburetor 1. Flows of fuel and air Starting When starting the engine, usethe choke, if necessary. By closing the choke valve, a rich mixture is supplied to help the enginestart easily, When the engine is started with the choke valve closed, the air in the carburetor is sucked rapidly into the crank-.
As a result, fuel is sucked through the main nozzle into the main bore and vaporized by the air streaming in through the hole in the choke valve before entering the crankcase. Flows of fuel and air At low speeds In the low speed range idling and trolling , the throttle valve is almost closed, When the crankcase pressure lowers, airfuel mixtures are sprayed into the main bore through the pilot outlet and bypass, The air sucked through the pilot air jet is mixed with the fuel sucked through.
When the throttle valve opens and passes the bypass hole or holes , fuel streams into the main bore. There are two bypass holes, and fuel is sprayed through one or two bypass holes depending on the throttle opening. NOTE: The pilot screw meters the flow of fuel at low speeds,and thus stabilizes the engine speed. So it must be set to specification. Flows of fuel and air At medium speeds When the throttle valve further opens, mixtures are supplied through the pilot outlet and two bypass holes.
In addition,. Note that even at wide open throttle, mixtures are supplied through the pilot outlet and bypass holes in the low speed circuit. At wide open throttle, the fuel metered by the main jet is mixed with the air metered by the main air jet in the main nozzle, and the resultant mixture is sucked into the main bore where it is vapor-. Before removing the carburetor, the front panel must be removed. For front panel removal, refer to page Disconnect the link connecting the throttle control lever to the throttle arm on the throttle arm side.
NOTE: 1. Both hinge pin and float can be removed, together with the needle valve. Check the carburetor body, its parts and the fuel and air passagesfor fouling or clogging. Clean fouled parts with suitable cleaning solvent, and blow out 1. Checking fuel and air passages clogged passageswith compressed air. Be sureto direct compressedair downward as cleaningsolvent may get in your eyes or those of other persons, or small carburetor parts may be blown off.
Checking the pilot screw Check the pilot screw for wear and replace it as required. Good condition. Checking jets and nozzle Check the air and fuel jets and nozzle for clogging, and clean, if necessary Checking check valves Check the check valves for cracks or chips and replace them as required.
Install the needle valve on the float, insert the hinge pin into the float hinge, and lock the hinge pin with the screw. NOTE : 1. The hinge pin should be fit in the slit in the carburetor and locked with the screw. When installing the float in the carburetor, placethe needlevalve in the valveseat.
Hold the float chamber to the mixing chamber with the four screws. NOTE: Make sure the rubber seal is attached to the float chamber. Install the spring, and screw in the pilot screw until lightly seated. Then back it out as specified. Float height Place the carburetor in an inverted position, and measure the distance from the contact surface of the float chamber with the mixing chamber to the top of the float using vernier calipers.
If the distance measured is out of the specification, replace the needle valve or float. Place the carburetor and silencer cover in the bottom cowling, and insert the bolts from the front of the bottom cowling into the silencer cover and carbure-.
Place the covers on the main and pilot air jet holes and bypass holes, and hold the plate with the two bolts,. Installation 1. Fit the two small holes in the gasket over the projections on the intake manifold.
Wiring removal Fuel hose Choke link Throttle wire Power head mounting bolt Exhaust manifold Manual starter Electric system CDI magneto Magneto base Intake silencer, carburetor Intake manifold and reed valve assembly Cylinder head cover and thermostat Exhaust covers Magneto basecontrol device Oil seal housing Crank upper Oil seal housing Crank lower Piston pin and piston Cylinder body and crankcase Piston clearance Piston rings Piston pins and bearings Crankshaft main bearings Important information.
Pistonand crankshaft Oil sealhousing Crank upper oil sealhousing Crank lower oil sealhousing Cylinder body Thermostat and cylinder head cover Reed valveassemblyand intake manifold Starter stay Limited throttle opening device Tool bag holder Carburetor and silencercover Engine installation Engineexternal parts installation To produce simultaneous ge ignidischar or capacit a rs, the two cylinde.
This model employs a cross scavenging system, and has an integrated cylinder and cylinder head. All dirt, mud, salt, and foreign material must be cleaned from the engine before the engine is removed and disassembled. This will help keep foreign material out of the engine. Before engine removal and disassembly, be sure that you have the proper tools and cleaning equipment. With them you can perform your work cleanly and effi-.
Disconnect the white lead of the stop switch at the joint. Next, remove the bolt holding the black lead, and disconnect the ground lead. During in their trays in parts and place them up speed order of disassembly. This will assembly and help assure that all parts are correctly reinstalled in the engine.
Secure an engine stand to a bench with 1. Fuel hose Remove the clip on the outlet side of the fuel filter, and remove the fuel hose from the filter. Throttle wire 1. Loosen the lock nuts of the two throttle wire adjust bolts, and remove the adjust bolts from the throttle wire stay.
NOTE: When disconnecting the fuel supply pipe, take care that fuel does not flow into the bottom cowling. Fuel can cause the mount rubbers and grommets to separate or become damaged. Exhaust manifold 1. Remove the three bolts, and remove the exhaust manifold from the cylinder body. NOTE: 2. After removing the exhaust manifold, insert the crankshaft into the engine stand gripped in a vice on a bench. The power head may not easily separate from the bottom cowling due to the gasket stuck to them.
If so, lever it off the bottom cowling with a piece of wood. Use care not to damage the bottom cowling or power head with a piece of wood. Remove the dowel pins from the bottom cowling or power head. To protect the dowel pins against damage, cover then with rags. Remove the bolt securing the limited throttle opening starting device, and re-. Loosen the band and take off the tool bag from the tool bag holder. Next, remove the tool bag holder from the cylinder body.
NOTE: The limited throttle opening starting device wire stay is fastened to the starter case set bolt. Electric system 1. Ignition coil Remove the spark plug caps from each upper and lower spark plug.
Remove the bolts and remove the ignition coil from the cylinder body. The major load must be carried in the direction of the arrow. If not, the holder can easily slip off. Keep the nut side flush with the crankshaft end until the flywheel comes off the tapered portion of the crankshaft.
Remove the three bolts, remove the base retainer and friction plate, and remove the retainer ring from the base retainer. Magneto base 1. One type of manual is called a repair manual and the other type is referred to as a factory service manual FSM. Repair manuals are handbooks published by 3rd party publishers, which is someone other than the manufacturer of the watercraft. Yamaha WaveRunner factory service manuals are manuals that are issued by the manufacturer and distributed to privately owned certified WaveRunner repair shops and dealership technicians.
Factory service manuals are highly detailed instruction books which cover serving, maintenance and repair. A Yamaha jet-ski repair manual is a repair book that gives repair instructions in laymen terms. It is geared toward DIY enthusiast.
New Products. Yamaha WR Series ! Our Price:. Description more details. Model: Yamaha WR Series ! With the throttle wide open, crank the engine until the reading on the compres- sion gauge stabilizes. Engine mount inspection 1. Oil strainer inspection 1. Oil tank installation 1. Oil breather plate bolt: 1st: 1. Oil pump installation 1. Maximum camshaft runout: 0. Camshaft-journal-to-camshaft- cap clearance: 0. Camshaft journal diameter: NOTE: Gradually tighten the intake and exhaust camshaft cap bolts in 2—3 steps in the sequence shown.
Cylinder head inspection 1. Cylinder head warpage limit: 0. Intake valve lifter Intake valve pad Intake valve cotter Intake valve upper spring seat Valve spring free length: Intake valve spring: Valve stem diameter a: Intake valve: 3. Calculate the valve stem-to-valve guide clearance as follows.
Replace the valve guide if out of specification. Install the new valve guide 2 by striking the special service tool from the camshaft side until the valve guide clip 3 contacts the cylinder head. NOTE: Apply engine oil to the surface of the new valve guide.
Eliminate carbon deposits from the valve with a scraper. Lap the valve slowly on the valve seat with a valve lapper commercially obtainable as shown.
Reface the valve seat with the valve seat cutter. Apply a thin, even layer of lapping com- pound onto the valve seat, and then lap the valve using a valve lapper commer- cially obtainable.
Compress the valve spring, and then install the valve cotter 1 using a thin screwdriver with a small amount of grease applied to it. After all of the bolts are fully loosened, remove them. Thoroughly wash the crankcase halves in a mild solvent. Thoroughly clean all the gasket surfaces and crankcase mating surfaces. Lubricate: Crankshaft journal bearings with the recommended lubricant Recommended lubricant: Engine oil 2. Crankshaft-pin-to-big-end- bearing clearance: 0.
Free up your time by fixing it right the first time. Troubleshooting Yamaha Big Bear Manual. Troubleshooting the Yamaha Big Bear is a form of problem solving when the ATV requires service due to a filed product. This Yamaha Big Bear manual contains a troubleshooting section to logically and systematically search for the source of the Yamaha Big Bear problem.
Common troubleshooting information for the Yamaha Big Bear usually includes:.
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