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

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.