Kohler M12 Engine

⚠ Explosive Fuel! Gasoline is extremely flammable.

1. Stop engine. Turn main fuel and idle fuel needles in until lightly bottomed.
2. Set preliminary settings by turning needles out per model.
3. Run engine at half-throttle 5-10 minutes to warm up.
4. Set main fuel needle midway between rich and lean at wide open throttle.
5. Set idle fuel needle at idle position; set idle speed to 1200 RPM.

Tools: Flat feeler gauge

1. Remove air cleaner assembly, carburetor, and breather assembly.
2. Position crankshaft so piston is at top of compression stroke.
3. Measure valve-to-tappet clearance with a flat feeler gauge (engine cold).
4. On M10-M16, adjust by turning the adjusting screw on tappets.
5. On M8, grind valve stems if too small, or replace valves if too large.

⚠ Overspeed Is Hazardous! Maximum allowable speed is 3600 RPM, no load.

Tools: Pliers

1. Make sure throttle linkage is connected to governor arm and carburetor throttle lever.
2. Pull governor arm away from carburetor as far as it will go.
3. Grasp end of cross shaft with pliers and turn counterclockwise as far as it will go.
4. Tighten palnut on governor arm to 15 in. lb.

Tools: Small screwdriver, .010 in feeler gauge

1. Invert carburetor; float tab rests on fuel inlet needle. Set 11/64 in (+ 1/32) clearance; bend tab to adjust.
2. Turn carburetor to normal position and let float drop; limit drop to 1-1/32 in; bend tab to adjust.
3. Check float-to-float-hinge-tower clearance with .010 in feeler gauge; file towers if needed.

1. Single cylinder: measure from the PTO end to the face of the block.
2. Twin cylinder: measure from the PTO end to the machined mounting surface of the closure plate.

1. Check the crankpin diameter of the unknown crankshaft.
2. Locate the matching dimension in the crankpin diameter column of the identification chart.
3. Compare main bearing and oil seal journal diameters to confirm the model series.
4. If diameters are shared by several models, check the Other Identifying Differences column.
5. Refer to the Common Features illustration at the start of each model section.

1. Remove the oil drain plug and dipstick. Tilt engine slightly toward drain hole.
2. Reinstall the drain plug and tighten securely.
3. Fill with new oil of the proper type to the F mark on dipstick.

1. Change oil while engine is still warm.
2. Change reduction gear unit oil if equipped; run engine briefly to distribute oil.
3. Drain fuel tank and fuel system (or run engine until empty).
4. Remove spark plug; add one tablespoon engine oil; reinstall plug without lead; crank two or three revolutions.
5. Turn engine until piston is at top of stroke; reinstall plug without lead.
6. Clean exterior surfaces and coat exposed metal with a light film of oil.
7. Store engine in a clean, dry place.

Tools: Flat feeler gauge or shim stock, Torque wrench

1. Install module, plain washers, and hex cap sems screws; move module away from flywheel and tighten slightly.
2. Insert .018 in flat feeler gauge between magnet and module.
3. Loosen screws so magnet pulls module down; tighten screws to 32 in. lb.
4. Remove feeler gauge; final air gap should be .012/.016 in.
5. Rotate flywheel to confirm magnet does not strike module.