16620-Z8D-305 Thermo Wax Assembly & 16600-Z8B-900 Choke Control - Fits Honda GCV160 GCV160A0 GCV160LA0 GCV190

16620-Z8D-305 Thermo Wax Assembly & 16600-Z8B-900 Choke Control - Fits Honda GCV160 GCV160A0 GCV160LA0 GCV19016620 Z8D 305 Thermo Wax, 16600 Z8B 900 Choke Control, and 16950 Z0Y 003 Fuel Valve Kit Key Features Complete automatic choke restoration kit designed to regulate engine startup behavior based on operating temperature. Thermo wax assembly utilizes precise thermal expansion properties to actuate the carburetor choke valve automatically without manual user adjustment. Mechanical choke control linkage plate ensures crisp, unhindered movement of the choke

16620-Z8D-305 Thermo Wax, 16600-Z8B-900 Choke Control, and 16950-Z0Y-003 Fuel Valve Kit

Key Features

• Complete automatic choke restoration kit designed to regulate engine startup behavior based on operating temperature.
• Thermo wax assembly utilizes precise thermal expansion properties to actuate the carburetor choke valve automatically without manual user adjustment.
• Mechanical choke control linkage plate ensures crisp, unhindered movement of the choke butterfly valve.
• In-line fuel shut-off valve features a fuel-resistant internal seal to completely cut off fuel supply during storage, maintenance, or transportation.
• Engineered to factory specifications to eliminate hard starting, rough idling, and black exhaust smoke caused by improper air-fuel ratios.

Replaces / Cross-Reference Part Numbers

• 16620-Z8D-305 - Thermo Wax Assembly: 16620-Z8D-305, 16620-Z8D-841, 16620-Z8D-842, 16620-Z9L-003
• 16600-Z8B-900 - Choke Control: 16600-Z8B-900
• 16950-Z0Y-003 - Fuel Shut-Off Valve: 16950-Z0Y-003

Compatibility & Fitment

• Compatible with Honda four-stroke overhead cam small engines.
• Fits specific engine models including: GCV160, GCV160A0, GCV160LA0, and GCV190.
• Fits Honda walk-behind lawn mower models including: HRR216 and HRX217.

When to Replace

• The lawn mower engine is extremely difficult to start from a cold rest or bogs down immediately after cranking.
• The choke plate stays permanently closed or open, leading to fuel flooding or an overly lean running condition.
• The thermo wax actuator cylinder pin is seized, bent, or fails to extend as the engine reaches operating temperature.
• Fuel continuously drips from the body of the fuel petcock switch or bypasses the valve when turned to the off position.

Installation Tips

• Disconnect the spark plug wire and allow the engine to cool down completely before handling fuel or mechanical linkages.
• Clamp the main fuel lines using line-clamping pliers or drain the gasoline tank entirely into an approved container before swapping the fuel shut-off valve.
• Take a digital photograph of the return spring and choke linkage orientation prior to disassembly to ensure accurate reinstallation alignment.
• Ensure the thermo wax capsule sits completely flush within its designated mounting bracket slot on the engine assembly to prevent binding.
• Manually cycle the choke control mechanism after final bolt tightening to verify the linkages move smoothly through their full range of motion.