The Honda 99101-ZH8-1150 Main Jet (#115) is a genuine OEM component designed for GX390, GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines. As a factory Honda part, this main jet carries the correct #115 orifice sizing that Honda specifies for these engines, ensuring the carburetor meters fuel at the right rate under load. Verify your engine's serial number against the fitment table before ordering, as Honda updates jet specifications at serial breaks within the same model family.
Key Features
- Correct Orifice Sizing — genuine OEM construction means the #115 bore is held to Honda's own specification, delivering the air-fuel ratio the carburetor was designed around
- Direct Carburetor Replacement — this jet installs directly into the carburetor bowl in place of the original, with no re-drilling or modification to the orifice
- Broad Engine Coverage — listed for GX390, GX630, GX660, GX690, GXV630, GXV660, and GXV690 engines; confirm your serial number matches the fitment table, as Honda supersedes jet part numbers at production breaks
- Full-Throttle Fuel Delivery — a correctly sized main jet keeps the engine running cleanly under full load; a worn or clogged jet causes rich running, sooting, or a lean stumble that robs power
The main jet is a small precision orifice fitted inside the carburetor float bowl. At mid to full throttle, fuel is drawn up through this jet and atomized into the incoming air charge — the diameter of the orifice controls exactly how much fuel enters the engine at those load points. When the main jet becomes clogged with varnish or debris, the engine runs lean and loses power or surges under load; if the orifice is worn oversized, the mixture runs rich, causing black smoke and fouled spark plugs. Replacing a faulty main jet with the correct OEM part restores the precise fuel metering the engine depends on for strong, clean performance.
Part Details
| Part Number | 99101-ZH8-1150 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#115) |
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.
