The Honda 99101-ZH8-1250 Main Jet (#125) is a genuine OEM carburetor component designed for GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines. As a direct Honda OEM part, it is manufactured to the exact calibration required by the factory carburetor, ensuring the fuel metering circuit performs as originally engineered. This jet is listed for both the horizontal shaft and vertical shaft variants in the 630, 660, and 690 displacement families — confirm part number 99101-ZH8-1250 and your engine's serial number against the fitment table before ordering, as Honda supersedes jet specifications at serial breaks.
Key Features
- Exact Orifice Calibration — the #125 sizing is the OEM specification for the main fuel metering circuit; an off-spec jet will richen or lean the mixture and rob the engine of its rated output.
- Genuine Honda OEM Part — sourced directly from Honda, this component meets the same standards as the jet installed at the factory, with no guesswork on orifice diameter or thread form.
- Broad Family Coverage — listed for GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines, spanning both horizontal and vertical shaft configurations in Honda's large-displacement V-twin line.
- Serial Number Verification Recommended — Honda revises carburetor jetting across production runs; check your engine's serial number against the fitment table to confirm this jet is correct for your specific unit.
- Restored Fuel Economy and Power — a clogged or damaged main jet starves the engine at mid-to-full throttle; replacing it with this OEM part restores clean fuel flow and proper air-fuel ratio across the operating range.
The main jet is the precision metering orifice at the heart of the carburetor's main circuit. Its calibrated bore controls how much fuel is drawn into the airstream under normal running and full-throttle conditions, so the engine receives the correct air-fuel mixture for complete combustion. When the jet becomes blocked by varnish or debris, or is worn oversize, the engine will run lean, surge, lose power, or refuse to reach full speed — symptoms that a new OEM jet, matched by part number 99101-ZH8-1250, directly corrects.
Part Details
| Part Number | 99101-ZH8-1250 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#125) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Horizontal Shaft Engine | 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.
