Kohler KT620 Generator Set

Tools: Feeler gauge, Torque wrench

1. Rotate crankshaft to establish TDC on compression stroke for cylinder 1.
2. Insert a 0.127 mm (0.005 in.) feeler gauge between end of 1 valve and rocker arm. Turn adjuster until slight drag is felt.
3. Hold in this position and tighten setscrew securely. Torque setscrew to 7.9 N·m (70 in. lb.). Recheck adjustment.
4. Repeat procedure for other valve on side 1.
5. Viewed from PTO end, rotate crankshaft 270° (3/4 turn) counterclockwise and align crankshaft keyway with cylinder 2.
6. Repeat steps for setting valve clearance on side 2.
7. Rotate crankshaft to check for free operation of valve train.

Tools: Tachometer, Pliers

1. Hold governor lever away from carburetor so throttle lever is against idle speed (RPM) adjustment screw. Start engine and warm up.
2. Adjust screw to set approximately 1450 RPM. Turn adjustment screw (inner) clockwise (in) to increase or counterclockwise (out) to decrease speed.
3. Release governor lever and check that throttle lever is in idle position. Obtain equipment manufacturer's recommended idle speed (1750 RPM).
4. Use a pliers to bend tab to achieve recommended governed idle speed.
5. Move throttle lever to wide-open/full throttle position. Turn high speed screw to obtain intended high speed no-load RPM.

⚠ Do not tamper with governor setting. Overspeed is hazardous and could cause personal injury.

Tools: 7 mm hex socket, Torque wrench

1. Make sure throttle linkage is connected to governor arm and throttle lever on carburetor.
2. Loosen nut holding governor lever to cross shaft.
3. Move governor lever toward carburetor as far as it will go (wide open throttle) and hold.
4. Round Cross Shaft End: Insert a long thin rod into hole on cross shaft and rotate counterclockwise as far as it will turn, then torque nut to 6.8 N·m (60 in. lb.).
5. 7 mm Hex Cross Shaft End: Use 7 mm hex socket on end of cross shaft and rotate counterclockwise as far as it will turn, then torque nut to 6.8 N·m (60 in. lb.).

Tools: Ammeter, DC voltmeter, AC voltmeter, Ohmmeter

1. Insert an ammeter in B+ lead from rectifier-regulator. With engine running at 3600 RPM, measure B+ to ground using a DC voltmeter.
2. If voltage is 13.8 volts or more, place a minimum load of 5 amps on battery to reduce voltage. Observe ammeter.
3. If charge rate increases when load is applied, charging system is OK and battery was fully charged.
4. If charge rate does not increase, remove connector from rectifier-regulator. With engine running at 3600 RPM, measure AC voltage across stator leads using an AC voltmeter.
5. Voltage is 28 volts or more: stator is OK; rectifier-regulator is faulty; replace.
6. Voltage is less than 28 volts: stator is faulty; replace. Test stator further using an ohmmeter.
7. With engine stopped, measure resistance across stator leads. Resistance is 0.064/0.2 ohms: stator is OK.
8. Resistance is 0 ohms: stator is shorted; replace. Resistance is infinity ohms: stator is open; replace.
9. Measure resistance from each stator lead to ground. Resistance is infinity ohms (no continuity): stator is OK. Resistance measured: stator leads are shorted to ground; replace.

Tools: Compression tester

1. Perform test on a warm engine.
2. Clean dirt away from base of spark plug(s) before removing them.
3. Ensure battery is fully charged, choke is off, and throttle is wide open during test.
4. Compression should be at least 160 psi and should not vary more than 15% between cylinders.

Tools: Water manometer, Rubber stopper, Pinch clamp, Tapered adapters

1. Insert rubber stopper into oil fill hole. Connect hose between stopper and one manometer tube. Leave other tube open. Check water level at 0 line.
2. Start engine and run no-load high speed.
3. Open clamp and note water level in tube. Level in engine side should be a minimum of 10.2 cm (4 in.) above level in open side.
4. If level is less than specified or pressure present, check for clogged or inoperative crankcase breather, leaking seals/gaskets, piston blow by, or restricted exhaust.
5. Close pinch clamp before stopping engine.

⚠ Carbon monoxide exhaust gases can cause severe nausea, fainting or death - never run engine indoors or enclosed

⚠ Rotating parts can cause severe injury - never operate with covers/shrouds/guards removed

Tools: Water manometer

1. Insert rubber stopper into oil fill hole; install pinch clamp on hose; use tapered adapters to connect hose between stopper and one manometer tube; leave other tube open to atmosphere; check water lev
2. Start engine and run no-load high speed
3. Open clamp and note water level in tube; level in engine side should be a minimum of 10.2 cm (4 in.) above level in open side
4. Close pinch clamp before stopping engine

⚠ Carbon monoxide can cause severe nausea, fainting or death

Tools: Dual Gauge Cylinder Leakdown Tester, 12mm x 14mm adapter (XT-6 engines)

1. Run engine until oil temperature reaches and maintains 150°F (66°C) or more for a minimum of 5 minutes under normal load
2. Remove spark plug(s) and air filter from engine
3. Rotate crankshaft until piston of cylinder being tested is at TDC of compression stroke; hold engine in this position with holding tool
4. Connect an air source (at least 100 PSI) to tool
5. Turn regulator knob counterclockwise; confirm both gauges read approximately the same pressure from 0 to 80 PSI; release pressure fully before proceeding
6. Install adapter hose into spark plug hole of cylinder being tested (use 12mm x 14mm adapter if required)
7. Firmly hold engine at TDC; connect adapter hose to tool quick connect; turn regulator knob clockwise until left gauge reads 20 PSI
8. Slowly turn regulator knob clockwise until left hand gauge maintains selected test pressure (80 PSI for engines over 200cc, 35 PSI for single cylinder push mower applications)
9. Compare right gauge reading to Test Pressure Chart to identify percentage of leakage
10. For engines exhibiting leakage in yellow or red zone, repeat test procedure after operating engine under normal load conditions

Tools: Rectifier-regulator tester

1. Connect tester ground lead (with spring clamp) to body of rectifier-regulator being tested.
2. Connect tester red lead to B+ terminal of rectifier-regulator and 2 black tester leads to 2 AC terminals.
3. Plug tester into proper AC outlet/power. Turn on power switch. POWER light should be illuminated.
4. Press TEST button until a click is heard and then release. Momentarily 1 of 4 status lights will illuminate indicating condition of part.
5. If OK (green) light comes on and stays steady, part is good and may be used.
6. Other lights come on: rectifier-regulator is faulty and should not be used.

1. Clean area around oil fill/dipstick. Remove drain plug and oil fill/dipstick. Allow oil to drain completely.
2. Clean area around oil filter. Remove filter. Wipe off mounting surface. Reinstall drain plug. Torque to 13.6 N·m (10 ft. lb.).
3. Place new filter in shallow pan with open end up. Fill with new oil until oil reaches bottom of threads. Allow 2 minutes for absorption.
4. Apply a thin film of clean oil to rubber gasket on new filter.
5. Refer to instructions on oil filter for proper installation.
6. Fill crankcase with new oil. Level should be at top of indicator on dipstick.
7. Reinstall oil fill/dipstick and tighten securely.
8. Start engine; check for oil leaks. Stop engine; correct leaks. Recheck oil level.
9. Dispose of used oil and filter in accordance with local ordinances.

⚠ Follow this procedure if engine will be out of service for 2 months or more

1. Add Kohler PRO Series fuel treatment or equivalent to fuel tank; run engine 2-3 minutes to get stabilized fuel into fuel system
2. Change oil while engine is still warm from operation (not required if using KOHLER PRO 10W-50 full-synthetic oil); remove spark plug(s) and pour about 1 oz. of engine oil into cylinder(s); replace spa
3. Disconnect negative (-) battery cable
4. Store engine in a clean, dry place

1. Add Kohler PRO Series fuel treatment or equivalent to fuel tank. Run engine 2-3 minutes.
2. Change oil while engine is still warm (not required if using KOHLER PRO 10W-50 full-synthetic oil).
3. Remove spark plug(s) and pour about 1 oz. of engine oil into cylinder(s). Replace spark plug(s) and crank engine slowly.
4. Disconnect negative (–) battery cable.
5. Store engine in a clean, dry place.