Kohler 18–25HP CH18, CH20, CH22, CH25 Command Engine Service Manual 1991–1997

Getting a vintage Kohler Command series engine back to factory specifications requires precise mechanical data. This official 184-page PDF manual (P/N 24 455 04-S) provides the exact diagnostic data and teardown overviews needed for 1991–1997 CH18, CH20, CH22, and CH25 horizontal crankshaft engines. Whether you are running a busy commercial shop or handling a complete backyard engine repair, referencing the exact factory clearances prevents catastrophic component damage. You can easily pull up the documentation on your shop tablet directly at the workbench to seamlessly guide you through the repair.

• Covers 1991–1997 Kohler Command CH18 to CH25 horizontal crankshaft models with standard electric start systems.
• Includes over 40 exploded-view diagrams and 10+ detailed wiring schematics for both standard and Electronic Fuel Injection (EFI) configurations.
• Details specific components including Keihin carburetors, Nikki carburetors, Impco LPG vaporizers, gerotor oil pumps, Smart-Spark ignition modules, hydraulic valve lifters, retractable recoil starters, and Motronic ECUs.
• Outlines essential workshop procedures like TPS initialization, cylinder leakdown testing, mechanical governor adjustment, recoil spring tension release, carburetor float height adjustment, fuel pressure measurements, and oxygen sensor diagnostics.

Engine Service and Diagnostic Scope

This document serves as the primary technical reference for diagnosing ignition, governor, and cooling system performance. The guide provides structured overviews of regular service intervals, oil and filter sequences, and air intake maintenance. You get comprehensive diagnostic flow charts, torque curves, horsepower performance graphs, fuel consumption curves, dimensional drawings, and oxygen sensor cutaway views designed to pinpoint common issues like starting difficulty, overheating, and power loss. Instead of throwing parts at a problem, technicians can rely on these factory workflows to systematically test lubrication circuits and retractable starter components. The manual also outlines step-by-step instructions for procedures that typically dictate an expensive dealership visit, such as safely relieving starter recoil spring tension, correctly performing the TPS initialization sequence, and conducting a cylinder leakdown test to evaluate engine integrity.

EFI System and Technical Specification Highlights

For EFI-equipped units, the manual details critical diagnostic data including fault code identification and pinout tables for both metal and plastic-cased ECUs. It lists essential electrical reference values for the oxygen sensor, oil temperature sensor, and throttle position sensor (TPS). You will also find exact engine assembly data, such as cylinder head fastener torque values set at 40.7 N·m (30 ft. lb.), a minimum intake valve lift of 8.07 mm, and crankcase breather cover mounting fasteners tightened to 8.6 N·m. Always ensure proper protective gear and standard workshop safety protocols are actively observed when working around high-pressure fuel systems and heavy engine components, and verify these values against your specific engine data plate before applying torque.