The Honda 99101-ZH8-1080 Main Jet (#108) is a genuine OEM carburetor component designed for a wide range of Honda horizontal shaft engines, vertical shaft engines, generators, two-stage snow blowers, and water pumps — including GX340, GX390, GX440, GX630, GX660, GX690, GXV630, GXV660, GXV690, EB3800, EB4000, EB5000, EB6500, EG5000, EG6500, EM3800, EM4000, EM5000, EM6500, HS928, HS1332, HS1336, HSM1336, HSS928, HSS1332, and WT40 equipment. Sourced directly from Honda, this main jet carries the exact #108 sizing that Honda engineers specify — so fuel metering stays precisely in specification rather than approximated. Because Honda supersedes carburetor jets at serial breaks, confirm your unit's serial number against the fitment table before ordering.
Key Features
- Correct #108 Orifice Sizing — the calibrated bore determines how much fuel the carburetor delivers at wide-open throttle; a worn or incorrect jet causes rich or lean running, rough power delivery, and excessive fuel consumption
- Genuine Honda OEM Part — manufactured to Honda's own specification, ensuring the metering diameter, thread pitch, and seat geometry match the original carburetor bore exactly
- Broad Fitment Across Multiple Equipment Classes — listed for GX-series and GXV-series engines, EB, EG, and EM generators, HS and HSS two-stage snow blowers, and the WT40 water pump, including models such as GX390, GX690, GXV690, EB5000, and EM6500
- Serial Number Verification Recommended — Honda updates carburetor jet specifications at production serial breaks; always cross-reference your machine's serial number with the fitment table to confirm part number 99101-ZH8-1080 is correct for your unit
The main jet is a precision-metered orifice seated inside the carburetor's main circuit. Its calibrated bore controls the volume of fuel drawn into the airstream under normal running and full-throttle conditions, which directly determines the air-to-fuel ratio the engine burns. When a main jet becomes clogged, eroded, or is replaced with an incorrectly sized unit, the engine will run too lean — causing overheating and power loss — or too rich, resulting in fouled spark plugs, poor fuel economy, and black exhaust smoke. Restoring the correct jet restores the fuel curve the carburetor was designed to deliver.
Part Details
| Part Number | 99101-ZH8-1080 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#108) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Generator | EB3800, EB4000, EB5000, EB6500, EG5000, EG6500, EM3800, EM4000, EM5000, EM6500 | All |
| Horizontal Shaft Engine | GX630, GX660 | 2060375-9999999 |
| Horizontal Shaft Engine | GX340, GX390, GX440, GX690 | All |
| Two-Stage Snow Blower | HS928, HS1332, HS1336, HSM1336, HSS928, HSS1332 | All |
| Vertical Shaft Engine | GXV630, GXV660, GXV690 | All |
| Water Pump | WT40 | 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.
