Yanmar 4TNV98CT turbocharged Engine

1. Adjust PTO link so toggle is overcenter 1-1/2 inches or 1/8 inch forward of parallel.
2. Set fulcrum bolt 2-1/2 inches from lock nut to clutch arm.
3. Adjust clutch spring so clutch arm to outside washer is 1-1/4 inches.
4. Adjust PTO brake to 1/32-inch gap with PTO engaged.

1. Remove pin from brake rod.
2. Turn clevis on brake rod until brake enters first notch of park lock.
3. Reinstall pin.

⚠ Prevent burns; do not touch engine shrouds or muffler if engine has been running.

1. Seat mixture needles lightly.
2. Back out high-speed needle 2 turns and idle needle 2-1/2 turns.
3. Start engine and allow to warm up.
4. At full throttle turn high-speed needle 1/8 turn until smooth.
5. At slow throttle turn idle needle 1/8 turn until smooth.
6. Check uniform acceleration; adjust high-speed if lean.

Tools: torque wrench, 0.100-inch spacer

1. Disconnect drag link from lever arm.
2. Loosen jam nuts on cross bolt.
3. Loosen jam nut and tapered stud several turns.
4. Tighten adjusting plug to 10 to 14 ft-lbs.
5. Adjust backlash with 0.100-inch spacer; tighten jam nuts to 40 ft-lbs.
6. Turn tapered stud snug; tighten jam nut to 40 ft-lbs.

⚠ Both valves must be completely closed.

Tools: feeler gauge, wrenches

1. Place valves without springs into valve guides.
2. Rotate crankshaft until piston is at TDC on compression stroke.
3. Check clearance between valve stem and tappet with feeler gauge.
4. Adjust tappet screw on K241AQS, K301AQS, K321AQS engines.
5. Grind valve stems to adjust clearance on K181QS engines.

⚠ Disconnect spark plug cable and ground.

Tools: 3/4-inch socket wrench

1. Place variable speed control lever in notch 5.
2. Pry button plug and loosen cap screw one to two turns.
3. Crank engine several revolutions until clutch pedal raises.
4. Push down on cap screw to take up slack.
5. Tighten cap screw and replace plug.

Tools: ohmmeter, timing light, feeler gauge

1. Connect ohmmeter or timing light per method used.
2. Rotate engine until breaker points just start to open.
3. Align S mark with indicator in timing sight hole.
4. Adjust breaker point gap slightly to correct.

⚠ Hydrogen and oxygen gases are explosive; keep sparks and flames away.

Tools: hydrometer, voltmeter

1. Check specific gravity with hydrometer.
2. Check battery voltage; should be 11.5 to 12.6 volts.
3. Crank engine 15 seconds and measure voltage.
4. Replace battery if voltage is less than 9.6 volts.
5. Charge battery if less than 75 percent charged.

⚠ Do not stretch diaphragm.

1. Scribe line across upper and lower housings.
2. Remove four cap screws and separate housings.
3. Remove cover and diaphragm.
4. Replace diaphragm, spring, check valves and gaskets.
5. Align scribe marks and tighten cap screws with actuating lever held.
6. Install pump and check for leaks.

Tools: socket and extension

1. Remove cotter pin and drilled pin from brake arm.
2. Remove left rear wheel.
3. Remove two cap screws through access holes.
4. Slip brake band off brake pulley.
5. Install new brake band and reverse disassembly.
6. Adjust brake linkage.

Tools: wrenches

1. Move variable speed control lever forward.
2. Push up secondary belt idler and remove secondary belt from variator.
3. Depress clutch pedal to clear brake pedal shaft.
4. Loosen primary belt guide at variator and remove primary belt.
5. Install new belt in opposite order.
6. Readjust variator.

Tools: wrenches

1. Move variable speed control lever forward.
2. Raise secondary belt idler and slip belt off variator.
3. Depress clutch pedal to clear brake pedal shaft.
4. Loosen three cap screws on transmission driven sheave.
5. Install new belt on variator and driven sheave.
6. Check variator and brake adjustments.