16620-Z8D-305 Thermo Wax Assembly & 16600-Z8B-900 Choke Control for Honda GCV160 GCV160A0 GCV160LA0 GCV160LA1 GCV190 GCV190LA HRX217 HRR216 Lawn Mower Engine Parts - with Spark Plug Gaskets

What It Is

This is a replacement thermo wax assembly (16620-Z8D-305) and choke control (16600-Z8B-900) set for Honda GCV160 and GCV190 engines. It automatically opens and closes the choke based on engine temperature, plus includes two spark plug gaskets. Designed for walk-behind mowers like HRX217 and HRR216, and other equipment using these Honda engines.

Fitment & Compatibility

Check your engine model number (stamped on the blower housing or valve cover). This fits:

• Honda GCV160 variants: GCV160A0, GCV160LA0, GCV160LA1
• Honda GCV190 variants: GCV190LA
• Honda mowers: HRX217, HRR216 series (with these engines)

Before buying: Verify your current part numbers match 16620-Z8D-305 (thermo wax) and 16600-Z8B-900 (choke control). These are OEM Honda parts—no aftermarket substitutes. The spark plug gaskets fit most Honda GCV engines (check your plug thread size). Deck size doesn’t matter; only engine model and existing part numbers count.

Key Things to Know

• Quality: Genuine Honda parts—reliable, but cost more than generic options. The thermo wax actuator is a known wear item on GCV engines, often failing after 3-5 years.
• Installation: Moderate difficulty. Requires removing the air filter housing, carburetor cover, and throttle linkage. Need basic tools (screwdrivers, pliers). Takes 20-40 minutes.
• Common gotchas: The thermo wax rod is fragile—don’t force it. The choke control linkage can be tricky to reattach; take a photo before removal. Spark plug gaskets are a bonus, but not always needed—check if your plug uses a crush washer.
• Performance: If your mower starts hard cold or runs rich (smoke, rough idle), this assembly is likely the cause. Replacing both parts together ensures proper choke operation.

Should You Buy It

Buy this if you have a Honda GCV160 or GCV190 engine with hard starting or poor cold-weather performance, and you want OEM reliability. Skip it if you’re comfortable with generic parts (cheaper, but may fail sooner) or if your choke issue is just a sticky linkage, not the thermo wax itself. For $15.99 with spark plug gaskets included, it’s a fair deal for a direct OEM fix.