OHV GTS 150 ENGINE SERVICE MANUAL Table Of Contents – Page 1 of 4 PREFACE SAFETY INFORMATION SAFETY TIPS SPECIFICATIONS GTS 150 ENGINE SPECIFICATION GTS 150 CARBURETOR SPECIFICATIONS GTS 150 FASTENER TORQUES TOOL REQUIREMENTS TROUBLESHOOTING ENGINE DOES NOT START WHEN "COLD" ENGINE WILL START "COLD", BUT WILL NOT START "HOT" ENGINE DOES NOT PRODUCE SPARK ENGINE HAS LOW COMPRESSION ENGINE FLOODED WITH FUEL ENGINE LACKS POWER BENT PUSH ROD ENGINE SURGING ENGINE BACK FIRES ENGINE AFTER FIRES ENGINE OVERHEATS E
OHV GTS 150 ENGINE SERVICE MANUAL Table Of Contents – Page 2 of 4 SECTION I CARBURETOR CARBURETOR DESCRIPTION CARBURETOR THEORY AND OPERATION CARBURETOR - REMOVAL CARBURETOR - PRESSURE TESTING CARBURETOR - DISASSEMBLY CARBURETOR - CLEANING AND SERVICE CARBURETOR - ASSEMBLY CARBURETOR - ADJUSTMENT SECTION 2 FUEL SYSTEM FUEL TANK - OPERATION FUEL TANK - REMOVAL FUEL TANK AND FILTER - CLEANING FUEL CAP - OPERATION FUEL CAP - SERVICE FUEL HOSE - REMOVAL FUEL HOSE - INSTALLATION SECTION 3 IGNITION OPERATION IGNI
OHV GTS 150 ENGINE SERVICE MANUAL Table Of Contents – Page 3 of 4 SECTION 5 ENGINE ENGINE - OPERATION INTAKE STROKE COMPRESSION STROKE POWER STROKE EXHAUST STROKE ENGINE DISASSEMBLY AIR CLEANER - OPERATION AIR CLEANER - REMOVAL REWIND STARTER.
OHV GTS 150 ENGINE SERVICE MANUAL Table Of Contents – Page 4 of 4 SECTION 5 ENGINE - continued PISTON AND CONNECTING ROD - REMOVAL PISTON RINGS - REMOVAL PISTON PIN - REMOVAL GOVERNOR ARM - REMOVAL ENGINE ASSEMBLY PISTON PIN - INSTALLATION PISTON RING - INSTALLATION PISTON - INSTALLATION CRANKSHAFT - INSTALLATION GOVERNOR SHAFT - INSTALLATION CAM FOLLOWERS - INSTALLATION CAMSHAFT - INSTALLATION GOVERNOR/SPLASHER- INSTALLATION SUMP - INSTALLATION 0IL PUMP - INSTALLATION BREATHER - INSTALLATION HEAD - ASSEMBL
PREFACE This Service and Overhaul Manual was written expressly for the following150 GTS Overhead Valve Engines: Model 97777 Type 0111-01 Model 97772 Type 0110-01 Model 97777 Type 31 10-01 MODEL & SERIAL NUMBER The ToroCompany has made every effort to make this service manual a useful and lasting addition to eve To assure proper and effective service, and to provide optimum performance for the life of the engine, you are read this manual carefully.
TABLE OF CONTENTS Reference Information .............................................................................................. SafetyInformation Page Specifications ............................................................................................................. ..................................................................................................... ........................................................................................................
TABLE OF CONTENTS Service Procedures (cont’d) Section 3 IgnitionSystem(cont’d) .......................................................................................................... Page armature coil wiring .................................................................................................... air gap adjustment..................................................................................................... 26 removal ................................................................
TABLE OF CONTENTS Service Procedures (cont’d) Section 5 Engine(cont’d) .................................................................................................... Page sump ................................................................................................................. governor and splasher ....................................................................................... cam shaft and cam followers ............................................................................
TABLE OF CONTENTS Service Procedures (cont'd) flywheelbrake .......................................................................................... Page 45 muffler .............................................................................................................. 45 dipsticktube ...................................................................................................... 46 ........................................................................................................
SAFETY INFORMATION This manual is intended as a service and repair manual only. The safety instructions provided in this manual are for the troubleshooting and service Manual of the engine only. The individual Operator's will contain safety information on the operation of the complete product powered by the GTS 150 engine.
SPECIFICATIONS GTS 150 Engine Specification led, llstroke overhead valve Measurementon page37 I counterclockwise as viewed from PTO Engine Rotation jet mainfixed with type Carburetor float unleaded regular Fuel 44 ounces (1.3 liters) solid state magneto type 22 degrees BTDC primary .2 .4 Ohms, secondary2400 - 5000 Ohms Champion RC12YC, gap .030" (.
SPECIFICATIONS (cont'd) GTS 150 Carburetor Specifications GTS 150 Fastener Torques Specifications - a GTS 150
TOOL REQUIREMENTS -Comments _- connecting rod, flywheel puller . _ . I valve adjusting nut _--__ valve adjustingj a m screw - I _ ^ -. (Nut driver acceptable) _ _ _ _ ~ r m Y -~- _ _ . _ I I p deep well for spark plug ~._- ---- _-_s_ B & S part number 19372 _.____I_____..
TROUBLESHOOTING Engine Does Not Start When “Cold” Engine Will Start “Cold”, but will Not Start “Hot” inadequate valve clearance readjust valves to .005 - .007”(.
TROUBLESHOOTING (cont'd) Engine Low Compression has incorrect valve clearance - readjust valves to .005 .007" (.15-.
TROUBLESHOOTING (cont’d) Bent Push Rod Engine Surging Engine Back Fires Engine After Fires Engine Overheats Engine Vibrates Excessively .
TROUBLESHOOTING (cont'd) Engine Crankshaft WillNot Turn Engine Produces Mechanical Knocking Sound Pre-Ignition . .
TROUBLESHOOTING (cont’d) Engine Stalls Spark Plug Fouled
GTS 150 MAINTENANCE Servicing Air Cleaner Replacing the Spark Plug Normally, clean the air cleaner after every25 operating Use a Champion RC12YC spark plug or equivalent. Th hours. More frequent cleaning is required when the mower correct air gapis .030"(.76mm). Remove the plug after is operated in dusty or dirty conditions. its condition. every 25 operating hours and check 1. Stop the engine, allow it to cool and disconnect the 1. Stop the engine, allow it to cool and disconnect the spark plug wire.
Removing Gasolinefrom the Fuel Tank 1. Stop the engine, allow it to cool and disconnect the spark plug wire. Remove the key switch on electric start models. 2. Remove the cap from the fuel tank and use a pump type siphon to transfer fuel into a clean gas canor container designedto hold gasoline. Note:this is the only fuel removal procedure that should be used for general maintenance. Changing Crankcase Oil 5.
1. Stop the engine, allow it to cool and disconnectthe spark plug wire. Remove the key on electric start models. TOP NO LOAD SPEED SCREW 2. Move the throttle controlto the "Fast" position. 3. Loosen the cable clamp screw until the throttlecable sheath can slidein its clamp. 4. Move the throttle cable left or rightuntil holes in the throttle lever and throttle bracket align. See 8 Figure IDLE MIXTURE THROTTLE BRACKET Figure 7 8.
Fuel can be in leftthe fuel tank only if a fuel additive such as Toro's Stabilizer/Conditioneris added to the gasoline Every25hours, or every cutting season, the engine blower and run through the engine before storage. housing must be removed andthe cooling fins cleaned. Failure to cleanthe cooling system may leadto engine Toro's Stabilizer/Conditioneris petroleum distillate based. overheating and severe engine damage.
SECTION 1 CARBURETOR Carburetor Description PILOT SYSTEM The carburetor used on GTS the 150 is a dual circuit (pilot and main), float bowl design with fixed main jet, fixed nonremovablepilotjetandanadjustablepilotcircuit mixture screw. The carburetor is fitted with a standard number 30 (.0295")mainjet. A highattitudemainjet number 28 (.0280") is also available. The carburetor is fitted with a stainless steel inlet needle and a replaceable inlet seat.
As the throttle plate is opened to compensate for engine 3. Disconnect the choke over-center spring. Note the load, the main discharge tube becomes the main source position of of thespringforcorrectassembly.See fuel.Opening the'throttle plateincreasestheflowofair Figure 15. through the venturi and strengthens the low pressure area at the main discharge tube. Fuel discharge increases at the main discharge tube as it decreases from the pilot system.
Carburetor Pressure.Testing 1. Turn the carburetor upside down. 2. Connect a pressure tester to the inlet fitting on the carburetor. See Figure17. IDLE STOP SCREW IDLE MIXTURE SCREW .- Figure 19 5. Thethrottle plateis retained with one screw. When th plate is removed the throttle shaft may be withdraw from the bodyof the carburetor. Figure 17 3. Pump the pressureto the inlet needle "popoff pressure, 5 psi (.3 kglcm 2). 4. The inlet needle should seal.
4. Use extreme care with mechanical cleaning devices: 10. Install the needle on the float. Put the float and needl in position and insert the hinge pin. i.e. wires, probes,tip cleaners, etc. Mechanical cleaning may damage or enlarge critically sized carburetor 1I Install . the float stop disc the andmain jet. components and passages. 12. Install the bowl gasket and the fuel bowl. Carburetor Assembly 13. Installthe bowl nut.
SECTION 2 FUEL SYSTEM FUEL TANK into the tank from an opening in the cap to allow gravity to feed fuel to the carburetor. Fuel lank Operation Fuel Cap Service The GTS150 uses a 1.6 quart (1.5 liters) plastic fuel tank with a non-replaceable75micron in-tankfilterscreen. The 1. The fuel cap may not be disassembled, however, the filter is welded in the bottomof the tank over a sediment vent opening on the cap and inner sealing disc sh reservoir.
breather vent tube. Leakage inthis area will allow dirt the to enter the air cleaner on the carburetor of side filter element. 5. Make sure the cork gasket is between the air cleaner body and the carburetor.Install the three5/16" hex, washer head shoulder screws. 6. Make sure the air cleaner element is properly cleaned and oiled, see Maintenance Section on page 15 and install the element. 7. Install the air cleaner cover and tighten the thumb screw.
SECTION 3 IGNITION operation The firing of the spark plug at the proper time is the culmination of a number of components working together. These components on the GTS 150 are: Flywheel Ignition armature coil Spark plug Armature coil wiring The following describes the function of each of the above components. - Figure 22 Ignition Operation Flywheel The flywheelis connected directlyto the crankshaft and as the crankshaft. Imbeddedin turns at the same speed the flywheel are three magnets.
5. Tighten the5/16" hex, washer head screws retaining the armature coilto 45 in Ibs (5Nm). INSULATOR 6. Remove the gas cap and replace the blower shroud. The blower shroud fasteners are tightened to 50 in Ibs (5.6Nm). 7. Install the gas cap. Ignition ArmatureCoil Removal E a Figure 23 1. Remove the gas cap. CHAMPION RC12YC .OW" (.76 mm) CAUTION: extreme careif there is fuel in the gas tank.Do not smoke or allow open flames around gasoline. Gasoline fumes are explosive. 2.
SECTION 4 REWIND STARTER Rewind Starter Operation 4. Remove thetwo ratchet dogs and springs. Take note of the positioning of the springsfor correct instal The rewind starter operates through a retainer/friction disc See Figure26. that causes two engagement dogs to extend from the center of the rewind starter and engage the inside of the starter cup on the flywheel. The engagement dogs move into contact withthe starter cup when the rewind rope is pulled.
4. Install the friction disc retainer and retainingscrew. See Figure30. Rewind Starter Assembly 1. Lubricate the center post of the rewind starter with a small amount of general purpose grease. 2. Place the reel assembly on the center post of the rewind starter and turn the reel counterclockwise until the hook on the reel spring engages the spring retainer 28. on the center post of the starter. See Figure SCREW Figure 30 I 5.
SECTION 5 ENGINE - Engine Operation Power Stroke When the piston comes to close TDC the mixture is ignite by the spark plug and the third stroke begins. The ing combustion gases push the piston indown the cylinder The GTS150 is a four stoke cycle, over head valve engine. creating the power stroke, both the intake and exhaust The running engine begins with the first of four strokes at this time. See Figure 34. being the intake stroke.
Engine Dissassembly Rewlnd Starter Operation See Section4 Rewind Starter on page 27. Air Cleaner Operation Rewind Starter Removal Combustion air comes from the fan blades on the flywheel air for the engine). Air (the flywheel also provides cooling 1. Removethefour5/16"hex,washerheadscrews an opening inthe moves into the air cleaner body through retaining the recoil starter to the blower housing. See an opening in the upperbody of the air blower housing and Figure cleaner.
Muffler Operation Flywheel Brake Operation (if installed) The muffler quiets exhaust noise by slowing the es Zone start mowers fitted are with a flywheel brake that kills the ignition and stopsthe rotation of the engine. The brake combustion gases while at the same time preventing is of adual chamber is a spring loaded lever that when released causes excessive a brake back pressure.
- - Carburetor Operation lgnltion Coli Removal See Section 1 - Carburetor, page 19. 1. Note the routingof the ignition ground (kill) wire, this will make reinstallation easier. Disconnect the ignition ground wire from the terminal on the back of the throttle bracket. See Figure45. - Carburetor Removal 1. Notethepositionofthechokeover-centerspring before removal. This will aid proper reinstallation. The long hook end of the spring is attached to the carburetor shaft.
2. Removethealternator. Flywheel Removal 1. Removethe 15/16"hex nut retainingtheflywheel starter cup. See Figure50. Alternator Operation The alternator is asingle coil employing 1/2wave rectification through the use of a diode built into the body of the Figure 50 alternator. The alternator also uses a capacitor in parallel with the outputfor electrical filtration. The diode can be checked with a ohmmeter by alternately placing the posi2. Remove the starter cup and reinstall the flywheel nut to the diode.
flywheel. Whenthe engine starts, thespeedoftheflywheel will exceed the speed of the starter motor helical shaft and will cause the pinion gear to move down the shaft disengaging from the flywheel ring gear. Electric Starter Removal (If installed) 1. Remove the two 3/8" hex, washer head cap screws retaining the starter. See Figure 52. Figure 54 Head Assembly Removal 1. Remove the four 1/2" hex, flange head cap screws that retain the head. It is not necessaryto remove the rocker arms at this time.
Head Disassembly 1. Hold the rocker arm adjusting nut with a 10 mm wrench and loosen the socket head jam screw a3 mm with hex key. See Figure57. Figure 59 Valves and Seats Reconditlonlng Figure 57 2. Remove the adjusting nuts and rocker arms. 3. The spring rate on the valve springs allows removal The intake and exhaust valve seats the on GTS 150 are factory cutto 44 degrees. The intake and exhaust valves are factory ground to 44.75 degrees.
Breather Operation in the top The crankcaseis ventilated through an opening (magneto) side of the block. The opening is under the flywheel and connectsto a passage with a sheet metal cover thatin turn ventilatesto the breatherin the side of the engine. Thecounterweightandconnectingrodthrow oil to a passage that leads to the head assembly. There is a hole in the sump side of the engine that allows oil to drain back from the head. Oil Pump Removal 1.
2. Clean the crankshaftof debris and any imperfections that could damage the sump crankshaft seal. It is recommended that a seal protectorbe put over the crankshaft or tape wrapped over the shaft to prevent damage to the seal. 3. Pull the sumpoff the engine. Camshaft Removal 1. Note the timing marks on the crankshaft drive gear and camshaft driven gear for proper assembly. 2. Turn the crankshaftso the connecting rod capis out of the way of the camshaft. 3.
camshaft which prevents the intake valve from fully seating. This, in turn, eases starting resistance. At operating speeds, centrifugal force will cause the to move arm out of the way of the cam lobe and will allow the intake valve to fully close, Compression Release Removal 1. If disassembly is necessary, take note of how the compression release lever and spring is installed, and pin punch. a drive the pivot out pinof the camshaft with 2. Notethatthepincanberemovedonlyfromone direction. See Figure68.
- Piston and ConnectingRod Removal A 1. Note the orientation of the piston and connecting rod prior to removal for proper reinstallation. There are matching arrows on the connecting rod and rod cap that point toward the push rods on assembly. See Figure 72. The word "Mag" is also writtenon the side of the connecting rod that should point toward the magneto side of the engine. VIEW AA Figure 74 3.
Engine Assembly Thoroughly inspect and clean al engine parts prior to "0" ringsshouldbe assembly. All movingpartsand lubricatedwith SAE 30 engine oil on installation. No sealant is required on head, valve cover, breather, muffler, carburetor or sump gaskets. Piston Pin Installation 1. Install one retaining ring in one side of the piston. 2. Make certain the arrow on the big end of the connecting rod and the arrowtheon face of the piston are on the same side. 3.
- Governor Shaft Installation Camshaft lnstallatlon 1. Place a flat washer on the governor shaft, against the 1. Match the timing mark on the camshaft with the timing upset on the shaft. See Figure 79. mark on the camshaft drive gear on the crankshaft. See Figure81. 2. Lubricate the governor shaft with SAE 30 engine oil: 3. Insert the shaft in the block of the engine. See Figure 79. I Figure 81 2. Lubricate the end of the camshaftSAE with 30engine oil and install the camshaft.
2. Install the gasket, breather assembly and its retaining screws. - Head Assembly 1. Lubricate the intake and exhaust valve stems with SAE 30 engine oil. 2. Install the intake and exhaust valves. The intake valve is the largerof the two valves. 3. Install the washer and valveseal on the stem of the intake valve. See Figure86. Figure 83 - Oil Pump Installation 1. Separate the gerotor set and insert the pump drive assembly so the slotinthe shaft engages the drive pin in the endof the camshaft.
Valve Clearance Adjustment Theengineshouldbecoolwhenadjustingthevalve clearance. 1. Bring the engine up to top dead centerwith bothvalves closed (compression stroke). 2. Turn the adjusting nut with10 a mm wrench until you have achieved a clearance .005" of to .007" (.I3 mm to .I8 mm). See Figure 87. 3. Tightenthevalvecoverscrews in adiagonalse- quence to 45 in Ibs (5 N-m). Throttle Bracket Installation 1. Install the two 3/8"hex,washerheadscrewsthat retain the throttle bracket to the engine block.
2. Install the governor lever on the governor shaft, leave the lever loose at this time. See Figure 92. . . .. 4. Install the choke over center spring. See Figure 95. . Figure 92 - Carburetor Installation - Governor Adjustment 1 . Install the carburetorthrottle arm on“Z”the bend of the Z bendis installed from the top 1. Toadjust the governorthefollowingsequenceof governor link rod. “The through the bushing inthe arm on the top of thethrottle component installation must be followed: shaft. a.
3. Set the ignition coil air gap (the space between the .008to- .012"(.20 .30mm). flywheel and ignition coil) Flywheel Installation 1. Install the flywheelkey. 4. Torque the ignition coil screws to45 in Ibs (5 N-m). 2. Make certain the crankshaft taper and flywheel taper 5. Route the spark plug wire through theinslot the front are free of burrs or defects. shroud bracketto help retainthe wire in place. 3. Installtheflywheel,startercupandflywheelnut. Torque the nut to 60 ft lbs (82 N-m).
3. Install a single 3/8"hex, washer head cap screw inthe front mounting bracket of the muffler. Torque the screw to 85 in Ibs (9.5 N-m) Muffler Shroud Installation 1. Install the shroud with two 3/8"hex, washer head screws inthe rearof the shroud. Torquethe screws to 50 in Ibs (5.5N-m) 2. Install two 5/16"hex, cap screws in the front of the 35 intoIbs (4 N-m). muffler shroud. Torque the screws See Figure101. Figure 103 Fuel Tank lnstallatlon 1.
Figure 105 2. Installtherecoilstarter with four 5/16" hex,cap screws. Make sure there is a flat washer on each screw. Torque the screws to 40 in Ibs ( 5 N-m) See Figure 106. 5. Make surethe foam element has been properly cleaned 15, and and oiled. See Maintenance Section on page install theelement. 6. Install the air cleaner cover and tighten the thumb screw. Spark Plug Installation 1, The correct spark plug is a Champion RC12YC. 2. Gap the plug to .030”(.76 mm). 3.
ACKNOWLEDGEMENT TheToro Company wishes to extend it's gratitute and appreciation to the studentsM. inLast's Steven Technical Illustration class in the Schoolof Technology at Ferris State University in Big Rapids, Michigan. The students identified in the photograph completed 93 of the illustrations used in this service manual. Students: left to right in photograph. Top row: Karen Becker, Scott Cooley, Kevin Lubien, Amada Lopez, Dan Backus.
