The Honda 99101-ZH8-1180 Main Jet (#118) is a genuine OEM fuel metering component designed for Honda GX390, GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines. As a factory-original part, it carries the precise orifice calibration Honda specifies for correct air-fuel ratio delivery across these engines. Confirm your engine's serial number against the fitment table before ordering, as Honda supersedes carburetor components at serial breaks and the correct jet number is critical to proper fueling.
Key Features
- Genuine OEM Fuel Calibration — manufactured to Honda's exact orifice specification, ensuring the #118 flow rate matches what the carburetor was designed to meter at wide-open throttle
- Direct OEM Replacement — this jet installs directly into the carburetor's main jet port, restoring the fuel delivery circuit without adaptation or rejettig
- Broad Horizontal and Vertical Engine Coverage — listed for GX390, GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines; check your serial number against the fitment table to confirm the correct application
- Correct Jetting Protects Engine Operation — a worn, clogged, or wrong-sized main jet causes lean or rich running conditions, leading to power loss, overheating, or excessive fuel consumption at load
The main jet is the primary fuel-metering orifice inside the carburetor's main circuit. At mid to full throttle, fuel is drawn through this precisely sized opening and mixed with incoming air before entering the combustion chamber. The jet's calibrated hole diameter — #118 in this case — determines how much fuel reaches the engine under load, and even a partial blockage or incorrect size will throw off the air-fuel mixture, robbing the engine of power and risking damage over sustained use. Replacing a clogged or damaged main jet with the correct OEM part restores proper fueling and brings engine performance back to specification.
Part Details
| Part Number | 99101-ZH8-1180 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#118) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Horizontal Shaft Engine | GX390, GX630, GX660, GX690 | All |
| Vertical Shaft Engine | GXV630, GXV660, GXV690 | All |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
