2001 Honda EU20i Generator Factory Service Manual (P/N 66Z0700)

Honda's EU20i shop manual, publication 66Z0700 (May 2001), covers the GX100-powered generator in L, G, B, F, W, S, U, and R configurations. Included Shop Manual News P/P-143 adds SK2 specifications, control-panel information, and wiring.

Navigation and wiring detail: Embedded bookmarks link to the chapters and supplement; PDF text search is not available. Small labels in the main wiring diagrams require zooming. Some SK2 wire-color codes remain difficult to distinguish when enlarged.

• GX100 engine repair: Cam pulley and timing-belt installation, crankshaft and piston service, cylinder inspection, valve-guide replacement, and valve-seat reconditioning.

• Generator diagnosis: Troubleshooting for low or missing AC/DC output, with stator, rotor, rectifier, and inverter unit fault isolation.

• Ignition and Oil Alert: Spark testing, ignition control module circuit checks, ignition pulse generator inspection, and oil level switch diagnosis.

• Fuel and throttle control: Carburetor removal, float-level checks, pilot-screw service, throttle motor testing, and fuel-pump inspection and replacement.

• Maintenance and starter repair: Scheduled maintenance, air-cleaner and fuel-tank service, valve-clearance adjustment, recoil starter rope replacement, and muffler removal.

• Electrical references: Variant-specific wiring diagrams, connector views, cable/harness routing, electrical test tables, and AC/DC performance curves.

This manual is suited to mechanics comfortable with engine teardown and multimeter diagnosis; valve-guide and bearing work requires additional shop equipment.

AC/DC Output, Ignition and ECO-Throttle Diagnosis

The no-output charts distinguish wiring and receptacle faults from stator, rotor, rectifier, or inverter faults. This helps narrow the cause before replacing an expensive inverter assembly.

Separate diagnostic paths address hard starting, stalling, unstable speed, and ECO-throttle response under load. Connector tests cover the ignition control module and Oil Alert circuitry. Stator resistance tables distinguish L, G/B/F/W/U, and S/R windings.

The operation chapter explains inverter voltage regulation, overload protection, full-transistor ignition, and engine stall prevention. Inverter service coverage consists of external diagnosis and unit replacement.

Because inverter testing involves hazardous voltage, have a qualified technician review the procedures if you lack electrical service experience.

GX100 Internal Engine Repair

The engine chapters cover crankcase separation, piston-ring and connecting-rod inspection, and bearing and oil-seal replacement. Cam-pulley alignment views document valve timing; maintenance standards provide wear limits, clearances, and component-specific torque values.

Valve work extends to guide reaming, seat cutting, and lapping. Honda's special-tool references identify the valve adjuster wrench 07708-0030400 and valve-guide driver 07JMD-KY20100, alongside bearing tools and valve-seat cutters.

The head-cover removal notes warn that forcing the cover can deform it.

Carburetor, Fuel System and Recoil Starter

Fuel-system coverage includes tank and filter cleaning, diaphragm-tube inspection, fuel-pump replacement, and carburetor insulator installation. Carburetor pages detail pilot-screw and limiter-cap replacement, throttle-stop adjustment, and throttle motor resistance and operation checks.

Carburetor coverage limitation: Printed page 5-4 is missing, leaving the carburetor disassembly section incomplete. The limiter-cap replacement notes also explain that removing the cap breaks the pilot screw.

Starter repair covers rope replacement, reel winding, and ratchet operation checks. Exploded assembly views show the recoil starter/fan cover and generator rotor/stator; adjacent sections document ignition-coil and rectifier testing.

Variant Wiring and Bench Reference Drawings

Five wiring diagrams cover G/F/B/W, U/R, S, L, and SK2 configurations. Control-panel drawings distinguish R/S types with and without parallel operation outlets, helping match the wiring layout to the generator on the bench.

Reference illustrations include AC/DC external characteristic curves, dimensional drawings, cam-pulley timing views, and piston assembly views. The electrical operation sections add inverter, ignition, and ECO-throttle block diagrams.

PDF Contents and Included SK2 Supplement

One printable English PDF contains the main shop manual and the August 2002 SK2 supplement. The 104-page PDF comprises 102 main-manual pages, including the front and back covers, plus the two-page Shop Manual News supplement; these additional pages are already included in the total.