Yanmar L4sV L70V L100V Engine

⚠ Do not use any sealant for this assembly.

Tools: Micrometer, Line or flare nut wrench

1. Verify actual piston TDC.
2. Leave the adjustment jig and spill-timing tool installed; return throttle to minimum speed.
3. Ensure the wooden wedge is in place and the flywheel has not rotated.
4. Observe the difference between actual and target timing; retarded timing requires reducing shim thickness, advanced requires increasing it.
5. Calculate required shim thickness (0.004 in. / 0.1 mm = 1° timing change).
6. Remove the fuel injection pump and shim(s); measure existing shim(s).
7. Install the calculated shim(s) over the mounting studs onto the crankcase mounting surface.
8. Install the fuel injection pump and rotate clockwise while tightening the mounting nuts.
9. Tighten mounting nuts to specification.
10. Remove the wedge and repeat timing procedures until correct.

⚠ Always use a wrench to hold the fuel injection pump fuel delivery valve to prevent loosening.

Tools: Fuel adjustment jig (P/N 114771-92310), Spill-timing tool, Line or flare nut wrench

1. Verify actual piston TDC.
2. Ensure the fuel injection pump is primed with fuel.
3. Remove the cooling fan housing and recoil starter.
4. Highlight the TDC timing mark on the cylinder cooling fin.
5. Highlight the TDC and target timing marks BTDC on the flywheel timing grid.
6. Remove the high-pressure fuel injection line.
7. Set the throttle control lever to the minimum speed position.
8. Remove the injection pump inspection window cover plate and gasket.
9. Install the fuel adjustment jig (Yanmar P/N 114771-92310) in the inspection window.
10. Install the spill-timing tool onto the fuel delivery valve.
11. Turn on the fuel supply and rotate the flywheel clockwise until fuel is pumped.
12. Slowly rotate crankshaft until the fuel level just begins to move, then stop.
13. Wedge the flywheel and check alignment of the target timing mark to the TDC mark.
14. If marks do not align, adjust the fuel injection timing.

Tools: Caliper

1. Measure the gap between pinion and pinion stop with the pinion at the projected position and pressed back lightly.
2. If not within specifications, adjust the dust covers to obtain the standard range.
3. Check the distance between the flywheel ring gear and starter motor pinion in the rest position (mesh clearance).

Tools: Feeler gauge, Wrenches

1. Remove the rocker arm (valve) cover bolts, valve cover and gasket.
2. Rotate the crankshaft to piston TDC of the compression stroke.
3. Check the valve clearance using a feeler gauge.
4. Loosen the adjusting screw locknut.
5. Turn the valve adjustment screw to adjust the clearance so there is slight drag on the feeler gauge.
6. Hold the adjusting screw while tightening the locknut and recheck the clearance.
7. Apply oil to the contact surface between the adjusting screw and push rod.
8. Install a new rocker arm (valve) cover gasket.
9. Install the rocker arm (valve) cover and bolts.

Tools: Wrenches

1. Confirm the speed lever return spring is in the upper mounting hole position.
2. Set the speed control lever to the OFF position, then push in on the end of the stop cable inner cable.
3. Measure the solenoid plunger travel; it should be 4.4 - 4.8 mm. Replace solenoid and/or cable if incorrect.
4. Set the speed control lever in the RUN position, lightly pull out on the inner cable and check the free play.
5. The correct free play is 0 - 0.5 mm between the cable end and the stop lever.
6. Thread the cable adjustment nuts forward or back to obtain the correct free play and tighten.

⚠ NEVER touch hot engine surfaces during operation and shortly after shut-down.

Tools: Compression Gauge Kit (Yanmar Gauge Set Code No. TOL-97190080)

1. Warm up the engine.
2. Stop the engine and remove the fuel injector from the cylinder head.
3. Crank the engine with the speed control at the stop position 5 to 6 compression strokes.
4. Install a gasket at the tip of the compression gauge adapter.
5. Install the compression gauge and adapter at the cylinder.
6. Crank the engine until the compression gauge reading is stabilized and at its maximum.
7. Remove the gauge and adapter; install the fuel injector and high pressure fuel injection line.

⚠ Batteries contain sulfuric acid. ALWAYS wear safety goggles and protective clothing. Flush affected area with clean water and obtain medical treatment if contact occurs.

1. Loosen nuts securing the battery hold-down and lift battery out of frame.
2. Fill the battery with electrolyte (approximately 1.9 qt / 1.8 L).
3. Remove the aluminum foil or sealing tape from the top of the battery.
4. Carefully fill with electrolyte up to the upper level line.
5. Let battery stand for half an hour to allow trapped gases to escape.
6. Top off battery with electrolyte if needed.
7. Install caps onto battery; hand-tighten.
8. Install battery into generator and reinstall hold-down; tighten nuts.
9. Connect battery cables and install boot onto the positive (+) terminal.

⚠ NEVER charge the battery while connected. Reversed polarity will damage the charger rectifier or the battery. Keep area well-ventilated away from sparks and open flames.

Tools: Battery charger

1. Disconnect the battery cables from the battery.
2. Clean terminals on the battery and clamps on the cable ends.
3. Connect the positive (+) clamp from the charger to the positive (+) terminal on the battery.
4. Connect the negative (-) clamp from the charger to the negative (-) terminal on the battery.
5. When finished charging, unplug the charger before disconnecting clamps from the battery.

Tools: Parts cleaner

1. Remove the oil filter retaining bolt.
2. Drain engine oil.
3. Pull the oil filter cap out and remove the oil filter.
4. Clean the oil filter in suitable parts cleaner or replace if damaged.
5. Lubricate the O-ring with oil and reinstall the oil filter.
6. Make sure the oil filter cap is fully seated.
7. Reinstall and tighten the oil filter retaining bolt.
8. Add new engine oil to the engine.
9. Warm up the engine for five minutes and check for leaks.

⚠ ALWAYS wear eye protection when using compressed air.

Tools: Compressed air 42 - 71 psi (0.29 - 0.49 MPa, 3.0 - 5.0 kgf/cm2)

1. Remove the wing nut and gasket.
2. Remove the air cleaner cover.
3. Remove the air cleaner element.
4. Inspect the element and determine if replacement is needed.
5. Clean the inside and outside of the air cleaner housing and cover.
6. Reinstall (or install new) air cleaner element into the housing.
7. Reinstall the air cleaner cover.
8. Reinstall the wing nut and gasket and hand-tighten.

⚠ Wipe up all spills immediately.

1. Clean the area around the fuel cap.
2. Remove the fuel cap from the fuel tank.
3. Lift out the inlet fuel screen.
4. Clean the inlet fuel screen or replace if damaged.
5. Inspect fuel cap gasket and replace if damaged.
6. Reinstall the inlet fuel screen.
7. Reinstall the fuel cap and hand-tighten.

⚠ Diesel fuel is flammable and explosive under certain conditions. Wipe up all spills immediately.

1. Position an approved container under the fuel tank to collect the fuel.
2. Remove the fuel cap.
3. Remove the fuel tank drain plug and gasket to drain the fuel.
4. Remove clamps and disconnect fuel supply and return lines.
5. Remove the fuel tank mounting bolts and remove the fuel tank.
6. Remove the three fuel filter nuts and pull the fuel filter out through bottom of the tank.
7. Install a new filter into the tank using a new O-ring.
8. Reinstall the three fuel filter nuts and tighten securely.
9. Reinstall the drain plug and gasket.
10. Reinstall the fuel tank and secure with mounting bolts.
11. Reconnect the fuel supply and return lines.
12. Fill the fuel tank with fuel and inspect for leaks.