The Honda 99101-ZJ4-1020 Main Jet (#102) is a genuine OEM component designed for GX610, GX620, GXV610, and GXV620 engines. As a direct Honda replacement, this jet is manufactured to the exact calibration required by the carburetor on these large-displacement engines. Confirm your engine's serial number against the fitment table before ordering, as Honda updates part numbers at serial breaks — part number 99101-ZJ4-1020 must match your specific build to deliver correct fueling.
Key Features
- Correct Fuel Metering — the #102 designation identifies the precise orifice size that governs the fuel-to-air ratio at wide-open throttle; an incorrect jet size causes rich or lean running that no amount of adjustment will fix
- Genuine OEM Construction — manufactured by Honda to the same specification as the jet installed at the factory, ensuring the orifice diameter is held to the tolerance the carburetor was calibrated around
- Broad V-Twin Coverage — listed for GX610 and GX620 horizontal shaft engines as well as GXV610 and GXV620 vertical shaft engines; confirm your model and serial number against the fitment table to verify this is the correct jet for your unit
- Serial-Number Sensitive — Honda supersedes carburetor jets at production breaks, so checking your engine's serial number before ordering is the single most important step to getting the right part
The main jet is a small, precisely drilled brass fitting seated inside the carburetor body. At wide-open or high-load throttle, fuel is drawn through the jet's calibrated orifice and mixed with incoming air before entering the combustion chamber. The orifice diameter — identified here by the #102 size code — directly controls how much fuel enters the mix: too small and the engine runs lean, overheats, and can suffer internal damage; too large and it runs rich, produces black smoke, and loses power. Replacing a worn, blocked, or incorrectly sized jet with the right genuine OEM part restores the precise fuel delivery these engines were designed to run on.
Part Details
| Part Number | 99101-ZJ4-1020 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#102) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Horizontal Shaft Engine | GX610, GX620 | All |
| Vertical Shaft Engine | GXV610, GXV620 | 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.
