Kohler Confidant ZT710 Service Manual

Kohler Confidant ZT710 Service Manual

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ZT710-ZT740
Service Manual
IMPORTANT:
Read all safety precautions and instructions carefully before operating equipment. Refer to operating
instruction of equipment that this engine powers.
Ensure engine is stopped and level before performing any maintenance or service.
2
Safety
3
5
Specifi cations
13
Tools and Aids
16
Troubleshooting
20
21
Fuel System
28
29
31
37
45
48
60
16 690 01 Rev. --
1

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Summary of Contents for Kohler Confidant ZT710

  • Page 1 ZT710-ZT740 Service Manual IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating instruction of equipment that this engine powers. Ensure engine is stopped and level before performing any maintenance or service. Safety Maintenance Specifi cations Tools and Aids Troubleshooting Air Cleaner/Intake...
  • Page 2 Safety SAFETY PRECAUTIONS WARNING: A hazard that could result in death, serious injury, or substantial property damage. CAUTION: A hazard that could result in minor personal injury or property damage. NOTE: is used to notify people of important installation, operation, or maintenance information. CAUTION WARNING WARNING...
  • Page 3 ² Have a Kohler authorized dealer perform this service. REPAIRS/SERVICE PARTS Kohler genuine service parts can be purchased from Kohler authorized dealers. To fi nd a local Kohler authorized dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada). 16 690 01 Rev. --...
  • Page 4 OIL RECOMMENDATIONS STORAGE If engine will be out of service for 2 months or more We recommend use of Kohler oils for best performance. follow procedure below. Other high-quality detergent oils (including synthetic) of API (American Petroleum Institute) service class SJ 1.
  • Page 5 Specifi cations Engine Dimensions with Low-Profi le Air Cleaner Dimensions in millimeters. Inch equivalents shown in [ ]. 16 690 01 Rev. -- KohlerEngines.com...
  • Page 6 Specifi cations Engine Dimensions with Heavy-Duty Air Cleaner Dimensions in millimeters. Inch equivalents shown in [ ]. KohlerEngines.com 16 690 01 Rev. --...
  • Page 7 Lubricate threads with engine oil prior to assembly. Any and all horsepower (hp) references by Kohler are Certifi ed Power Ratings and per SAE J1940 & J1995 hp standards. Details on Certifi ed Power Ratings can be found at KohlerEngines.com.
  • Page 8 Specifi cations TORQUE SPECIFICATIONS ZT710 ZT720 ZT730 ZT740 Crankcase Breather Assembly Breather Reed Cover Stud 6.2 N·m (55 in. lb.) into new hole 4.0 N·m (35 in. lb.) into used hole Breather Reed Cover Hex Nut 1.3 N·m (12 in. lb.) Breather Cover Fastener 8.5 N·m (75 in.
  • Page 9 Specifi cations TORQUE SPECIFICATIONS ZT710 ZT720 ZT730 ZT740 Retractable Starter Mounting Screw 7.3 N·m (65 in. lb.) Center Screw 5.0-6.0 N·m (44-54 in. lb.) Solenoid (Starter) Mounting Hardware 4.0-6.0 N·m (35-53 in. lb.) Nut, Positive (+) Brush Lead 8.0-11.0 N·m (71-97 in. lb.) Speed Control Bracket Fastener 10.7 N·m (95 in.
  • Page 10 Specifi cations CLEARANCE SPECIFICATIONS ZT710 ZT720 ZT730 ZT740 Crankshaft End Play (free) 0.075/0.595 mm (0.0030/0.0023 in.) Bore (in crankcase) 40.974/40.987 mm (1.6131/1.6137 in.) Max. Wear Limit 41.000 mm (1.6142 in.) Bore (in oil pan) 40.974/41.000 mm (1.6457/1.6142 in.) Crankshaft Bore (in oil pan)-to-Crankshaft Running Clearance 0.039/0.087 mm (0.0015/0.0034 in.) Flywheel End Main Bearing Journal O.D.
  • Page 11 Specifi cations CLEARANCE SPECIFICATIONS ZT710 ZT720 ZT730 ZT740 Piston, Piston Rings, and Piston Pin Piston-to-Piston Pin Running Clearance 0.006/0.017 mm (0.0002/0.0007 in.) Pin Bore I.D. 17.006/17.012 mm (0.6695/0.6698 in.) Max. Wear Limit 17.025 mm (0.6703 in.) Pin O.D. 16.995/17.000 mm (0.6691/0.6693 in.) Max.
  • Page 12 Specifi cations GENERAL TORQUE VALUES English Fastener Torque Recommendations for Standard Applications Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 or 5 Fasteners Into Aluminum Size Grade 2 Grade 5 Grade 8 Tightening Torque: N·m (in. lb.) ± 20% 8-32 2.3 (20) 2.8 (25)
  • Page 13 Here is a list of tools and their source. SEPARATE TOOL SUPPLIERS Kohler Tools SE Tools Design Technology Inc. Contact your local Kohler source of 415 Howard St. 768 Burr Oak Drive supply. Lapeer, MI 48446 Westmont, IL 60559...
  • Page 14 For reaming worn valve guides to accept replacement oversize valves. Can be used in low-speed drill press or with handle below for hand reaming. Reamer Handle Design Technology Inc. For hand reaming using Kohler 25 455 12-S reamer. DTI-K830 Valve Guide Service Kit (Courage, Aegis, Command, OHC) SE Tools KLR-82415 For servicing worn valve guides.
  • Page 15 Tools and Aids FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL A fl ywheel holding tool can be made out of an old junk A spanner wrench to lift rocker arms or turn crankshaft fl ywheel ring gear and used in place of a strap wrench. may be made out of an old junk connecting rod.
  • Page 16: Troubleshooting

    Troubleshooting TROUBLESHOOTING GUIDE When troubles occur, be sure to check simple causes which, at fi rst, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank. Some general common causes of engine troubles are listed below and vary by engine specifi cation. Use these to locate causing factors.
  • Page 17 Troubleshooting EXTERNAL ENGINE INSPECTION Engine Loses Power NOTE: It is good practice to drain oil at a location away ● Dirty air cleaner element. from workbench. Be sure to allow ample time for ● Engine overheated. complete drainage. ● Excessive engine load. ●...
  • Page 18 Troubleshooting CRANKCASE VACUUM TEST WARNING WARNING Carbon Monoxide can cause severe nausea, Rotating Parts can cause severe injury. fainting or death. Stay away while engine is in operation. Avoid inhaling exhaust fumes. Engine exhaust gases contain poisonous carbon Keep hands, feet, hair, and clothing away from all monoxide.
  • Page 19 Troubleshooting COMPRESSION TEST For Command Twins: A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s) before removing them. Be sure choke is off, and throttle is wide open during test. Compression should be at least 160 psi and should not vary more than 15% between cylinders.
  • Page 20: Air Cleaner/Intake

    Air Cleaner/Intake AIR CLEANER Move bails on air cleaner cover up; remove latches from cover; remove cover. These systems are CARB/EPA certifi ed and components should not be altered or modifi ed in any way. Precleaner (if equipped) Heavy-Duty Air Cleaner Components 1.
  • Page 21: Fuel System

    3. Connect pulse line to new fuel pump and make sure Low permeation fuel line must be installed on carbureted opposite end is properly connected into valve cover. Kohler Co. engines to maintain EPA and CARB regulatory compliance. 4. Attach new fuel pump using screws. Torque screws to 2.8 N·m (25 in.
  • Page 22 Fuel System CARBURETOR Walbro One-Barrel Carburetor Components WARNING Explosive Fuel can cause fi res and severe burns. Do not fi ll fuel tank while engine is hot or running. Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl...
  • Page 23 Fuel System Troubleshooting-Carburetor Related Causes Condition Possible Cause Conclusion Engine runs rich (indicated by black, Clogged air cleaner. Clean or replace air cleaner. sooty exhaust smoke, misfi ring, loss Choke partially closed during Check choke lever/linkage to ensure of speed and power, governor operation.
  • Page 24 Fuel System Carburetor Adjustments Float Setting (Keihin Only) NOTE: Carburetor adjustments should be made only after engine has warmed up. Carburetor is designed to deliver correct fuel-to-air mixture to engine under all operating conditions. Main fuel jet is calibrated at factory and is not adjustable. Idle fuel adjusting needles are also set at factory and are not adjustable.
  • Page 25 1219 meters (4000 ft.). To obtain high altitude kit information or to fi nd a Kohler authorized dealer visit 24. Install slow jet and new plug into end of slow jet KohlerEngines.com or call 1-800-544-2444 (U.S. and tube.
  • Page 26 Fuel System UNITIZED THROTTLE AND CHOKE CONTROL Some engines are equipped with a unitized throttle and choke control. This assembly controls choke and engine speed with a single lever. Engines with a unitized throttle and choke control will have either a left side pull or a right side pull.
  • Page 27 If starter does not turn engine over, shut starter off immediately. Do not make further attempts to start engine until condition is corrected. Do not jump start using another battery. See your Kohler authorized dealer for trouble analysis. 4. For Operation – After engine starts, move throttle/...
  • Page 28: Governor System

    Governor System GOVERNOR Governed speed setting is determined by position of throttle control. It can be variable or constant, depending on engine application. Governor is designed to hold engine speed constant under changing load conditions. Most engines are equipped with a centrifugal fl...
  • Page 29: Lubrication System

    Lubrication System This engine uses a combination pressure/splash lubrication system, delivering oil under pressure to crankshaft, connecting rod and main bearing surfaces. Other component areas are splash lubricated. A high-effi ciency gerotor oil pump maintains high oil fl ow and oil pressure, even at low speeds and high operating temperatures.
  • Page 30 Lubrication System OIL SENTRY (if equipped) Installation ™ NOTE: Make sure oil level is checked before each use, 1. Apply pipe sealant with Tefl on ® (Loctite ® ® 592™ and is maintained up to FULL or F mark on Thread Sealant or equivalent) to threads of switch.
  • Page 31: Electrical System

    Electrical System SPARK PLUGS Inspection Inspect each spark plug as it is removed from cylinder CAUTION head. Deposits on tip are an indication of general Electrical Shock can cause injury. condition of piston rings, valves, and carburetor. Do not touch wires while engine is running. Normal and fouled plugs are shown in following photos: Normal Spark Plug Component and Details...
  • Page 32 Electrical System Carbon Fouled Battery Maintenance Regular maintenance is necessary to prolong battery life. Battery Test To test battery, follow manufacturer's instructions. ELECTRONIC IGNITION SYSTEMS All ignition systems are designed to be trouble free for life of engine. Other than periodically checking/replacing spark plugs, no maintenance or timing adjustments are necessary or possible.
  • Page 33 Electrical System Ignition System These systems use a capacitive discharge (CD) coil. With CDI fi xed timing, ignition timing and spark remains constant regardless of engine speed. Timing of spark is controlled by location of fl ywheel magnet group as referenced to engine TDC.
  • Page 34 Electrical System Electronic Ignition Systems Tests NOTE: Ignition tester must be used to test ignition on these engines. Use of any other tester can result in inaccurate fi ndings. Battery on unit must be fully charged and properly connected before performing tests (a battery that is hooked up or charged backward will crank engine but it won’t have spark).
  • Page 35 Electrical System BATTERY CHARGING SYSTEM NOTE: Observe following guidelines to avoid damage to electrical system and components: ● Make sure battery polarity is correct. A negative (–) ground system is used. ● Disconnect rectifi er-regulator plug and/or wiring harness plug before doing any electric welding on equipment powered by engine.
  • Page 36 Electrical System 12/15/25 Amp Battery Charging Systems NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should be made with engine running at 3600 RPM with no load. Battery must be good and fully charged. When problems occur in keeping battery charged or battery charges at high rate, charging system or battery might be causing problems.
  • Page 37: Starter System

    Starter System NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool-down period between starting attempts. Failure to follow these guidelines can burn out starter motor. NOTE: If engine develops suffi cient speed to disengage starter but does not keep running (a false start), engine rotation must be allowed to come to a complete stop before attempting to restart engine.
  • Page 38 If splines are dirty, clean them with solvent. 7. Splines should have a light fi lm of lubricant. Lubricate as necessary with Kohler starter drive lubricant. Reinstall or replace drive components, assembling them in reverse order they were removed.
  • Page 39 5. Install thru bolts and torque to 4.5-5.7 N·m Plate Plug (40-50 in. lb.). Solenoid Frame and Field 6. Lubricate drive shaft with Kohler starter drive Brush Holder lubricant. Install drive components following Commutator End instructions for servicing starter drive. Screw...
  • Page 40 Brush Replacement 4 brushes and springs are serviced as a set. Use a new Kohler brush and spring kit if replacement is necessary. 1. Perform steps 1-5 in Starter Disassembly. 2. Remove screws securing brush holder assembly to end cap (plate).
  • Page 41 Starter System 10. Starter reassembly when replacing brushes/brush Starter Reassembly holder assembly: NOTE: Always use a new retainer. Do not reuse old a. Hold starter assembly vertically on end housing, retainers that have been removed. and carefully position assembled brush holder NOTE: Correctly installed, center pivot section of drive assembly, with supplied protective tube, against lever will be fl...
  • Page 42 Starter System Solenoid Tests NOTE: DO NOT leave 12 volt test leads connected to solenoid for any time over what is necessary for performing each of individual tests. Internal damage to solenoid may occur. Disconnect all leads from solenoid including positive brush lead attached to lower stud terminal. Remove mounting hardware and separate solenoid from starter for testing.
  • Page 43 Starter System RETRACTABLE STARTERS WARNING Retractable starters contain a powerful, recoil spring that is Uncoiling Spring can cause severe injury. under tension. Always wear safety goggles when servicing retractable starters and carefully follow instructions in Wear safety goggles or face protection when Retractable Starter for relieving spring tension.
  • Page 44 Starter System Remove Starter Pawls (dogs) Replacement 1. Remove screws securing starter to blower housing. 1. Install a clamp to hold pulley in starter housing and prevent it from rotating. 2. Remove starter assembly. 2. Unscrew center screw and lift off drive plate. Rope Replacement 3.
  • Page 45 To Carburetor Filter For engine to be Tier III compliant, it may be fi tted with a Kohler supplied canister vapor recovery system, or a system developed and installed by Original Equipment Manufacturer (OEM). Details on Kohler system are included below.
  • Page 46 Emission Compliant Systems SECONDARY EMISSION COMPLIANT SYSTEM Twin Secondary Air Induction System Hose To Exhaust Secondary Air Inlet Screen Hose To Carburetor Manifold Valve Assembly Hose To Exhaust Manifold Single Secondary Air Induction System Secondary Air Hose To Exhaust Hose To Carburetor Inlet Screen Valve Assembly Manifold...
  • Page 47 Emission Compliant Systems Remove Inlet Screen Inlet Components Secondary Air Valve Assembly Barb Inlet Screen 1. Remove inlet screen from secondary air valve assembly by grasping inlet screen at base and gently pulling away from valve assembly. 2. Use a soft brush to remove debris from screen. 3.
  • Page 48 Disassembly/Inspection and Service WARNING Before working on engine or equipment, disable engine as Accidental Starts can cause severe injury or follows: 1) Disconnect spark plug lead(s). 2) Disconnect death. negative (–) battery cable from battery. Disconnect and ground spark plug lead(s) before servicing.
  • Page 49 Disassembly/Inspection and Service Clean all parts thoroughly as engine is disassembled. Remove Blower Housing and Outer Baffl es Only clean parts can be accurately inspected 1. Remove air cleaner cover. and gauged for wear or damage. There are many commercially available cleaners that will quickly remove 2.
  • Page 50 Disassembly/Inspection and Service Remove Air Cleaner and Carburetor Remove Inner Baffl es Remove mounting screws securing inner baffl es to WARNING crankcase. Note position of any lifting bracket(s). Remove inner baffl es. Explosive Fuel can cause fi res and severe burns.
  • Page 51 Disassembly/Inspection and Service Cylinder Head Components Gasket Valve Cylinder Head Valve Spring Cap Valve Stem Seal Valve Spring Valve Spring Keeper Stud Spark Plug Guide Plate Push Rod Rocker Arm Rocker Arm Pivots Adjusters Washer Valve Cover Remove Spark Plugs Remove Cylinder Heads Remove spark plug from each cylinder head.
  • Page 52 Disassembly/Inspection and Service 3. Once valve spring is compressed, remove following 4. Repeat above procedure for other cylinder head. Do items. not interchange parts from 1 cylinder head to another. ● Valve spring keepers. ● Valve spring caps. ● Valve springs. ●...
  • Page 53 Disassembly/Inspection and Service Valve Guides Flywheel/Ignition/Breather Components If a valve guide is worn beyond specifi cations, it will not guide valve in a straight line. This may result in burnt valve faces or seats, loss of compression, and excessive oil consumption. To check valve guide-to-valve stem clearance, thoroughly clean valve guide and, using a split-ball gauge, measure inside diameter of guide.
  • Page 54 fl ywheel, crankshaft, and key if fl ywheel key is sheared or keyway is damaged. Inspect ring gear for cracks or damage. Kohler does not provide ring gears as a serviceable part. Replace fl ywheel if ring gear is damaged.
  • Page 55 Disassembly/Inspection and Service 3. Carefully inspect governor gear shaft and replace it Remove Oil Pan Assembly only if it is damaged. After removing damaged shaft, 1. Remove screws securing oil pan to crankcase. press or lightly tap replacement shaft into oil pan to depth shown.
  • Page 56 Piston Ring Set Piston Pin Retainer be checked for wear or damage. Whenever tappets are Piston Piston Pin replaced, apply a liberal coating of Kohler lubricant to base of each new tappet before it is installed. Connecting Rod Connecting Rod End Cap...
  • Page 57 Disassembly/Inspection and Service Normally, very little wear takes place in piston boss- Connecting Rods piston pin area. If original piston and connecting rod can Offset, stepped-cap connecting rods are used in all be reused after new rings are installed, original pin can these engines.
  • Page 58 (refer to Specifi cations). scoring, grooving, etc., no further reconditioning is Oversize Kohler replacement piston will then fi t necessary. If bearing surfaces are worn or damaged, correctly.
  • Page 59 Disassembly/Inspection and Service 3. When bore is within 0.064 mm (0.0025 in.) of Use following procedure to accurately measure piston- desired size, remove coarse stones and replace to-bore clearance: them with burnishing stones. Continue with 1. Use a micrometer and measure diameter of piston burnishing stones until bore is within 0.013 mm 6 mm (0.2362 in.) above bottom of piston skirt and (0.0005 in.) of desired size and then use fi...
  • Page 60 Reassembly NOTE: Make sure engine is assembled using all Install Breather Filter and Outer Cover specifi ed torque values, tightening sequences, and clearances. Failure to observe specifi cations Fastener Torque Sequence and Sealant could cause severe engine wear or damage. Always use new gaskets.
  • Page 61 Reassembly Crankshaft/Governor Gear/Oil Pump Components Install Governor Cross Shaft 1. Lubricate governor cross shaft bearing surfaces in crankcase with engine oil. 2. Slide lower washer onto governor cross shaft and install cross shaft from inside of crankcase. 3. Install nylon washer onto governor cross shaft, then start push-on retaining ring.
  • Page 62 Reassembly 4. Make sure FLY stamping on piston is facing toward Install Oil Seal in Oil Pan fl ywheel side of engine. Use a hammer with a rubber or wood grip and gently tap piston into cylinder. Be Oil Seal Component and Detail careful oil ring rails do not spring free between bottom of ring compressor and top of cylinder.
  • Page 63 Reassembly Install Oil Pan Assembly Flywheel/Ignition/Breather Components Sealant Pattern Fastener Torque Sequence RTV sealant is used as a gasket between oil pan and crankcase. Refer to Tools and Aids for a listing of approved sealants. Always use fresh sealant. Using outdated sealant can result in leakage.
  • Page 64 Reassembly Install Breather Reed and Outer Cover Install Flywheel and Fan Breather Cover Sealant CAUTION Damaging Crankshaft and Flywheel can cause personal injury. Using improper procedures can lead to broken fragments. Broken fragments could be thrown from engine. Always observe and use precautions and procedures when installing fl...
  • Page 65 Reassembly Cylinder Head Components Gasket Valve Cylinder Head Valve Spring Cap Valve Stem Seal Valve Spring Valve Spring Keeper Stud Spark Plug Guide Plate Push Rod Rocker Arm Rocker Arm Pivots Adjusters Washer Valve Cover 1. Check to make sure there are no nicks or burrs on Assemble and Install Cylinder Heads sealing surfaces of cylinder head or crankcase.
  • Page 66 Reassembly Adjust Valve Clearance Install Valve Covers Valve Cover RTV Sealant Adjusters Retaining Push Rods Adjuster Rocker Arm 1. Rotate crankshaft to establish TDC on compression stroke for cylinder 1. Check for: a. Compression will be felt through spark plug hole. RTV Sealant b.
  • Page 67 Reassembly Install Spark Plugs 1. Check gap using wire feeler gauge. Adjust gap to 0.76 mm (0.03 in.). 2. Install plug into cylinder head. 3. Torque plug to 27 N·m (20 ft. lb.). External Engine Components Fixed Guard Air Cleaner Cover Debris Screen Blower Housing Hose Clamp...
  • Page 68 Reassembly Install Ignition Modules Install Rectifi er-Regulator (if equipped) 1. Rotate fl ywheel to position magnet away from 1. Install B+ terminal/lead into center position of ignition module bosses. rectifi er-regulator plug so it locks in place, and connect plug to rectifi er-regulator. 2.
  • Page 69 Reassembly 4. Install a new air cleaner base gasket and air cleaner Install External Governor Controls base onto mounting studs. Torque nuts to 6.2-7.3 N·m (55-65 in. lb.). Control Bracket Components 5. Connect breather hose to air cleaner base and secure with clamp.
  • Page 70 Reassembly Install Blower Housing Fuel Pump Components NOTE: Do not completely tighten screws until all are installed to allow shifting for hole alignment. 1. Install blower housing onto engine. Start all mounting screws. Make sure wire harness and spark plug leads exit out through appropriate openings in shrouding.
  • Page 71 Reassembly Connect Spark Plug Leads Connect leads to spark plugs. Prepare Engine for Operation Engine is now completely reassembled. Before starting or operating engine, be sure to do following. 1. Make sure all hardware is tightened securely. 2. Make sure oil drain plug, Oil Sentry pressure switch, and a new oil fi...
  • Page 72 © 2013 by Kohler Co. All rights reserved. KohlerEngines.com 16 690 01 Rev. --...

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