The Honda 99101-ZH8-0780 Main Jet (#78) is a genuine OEM carburetor component designed for a wide range of Honda generators, horizontal shaft engines, and two-stage snow blowers, including the EB3500, EB3800, EB4000, EB5000, EB6500, EM3500, EM3800, EM4000, EM5000, EM6500, EU3000, EX3300, GX200, GX240, GX270, HS724, and HSS724. As a direct Honda OEM replacement, this main jet is manufactured to the exact size and flow specification Honda's own engineers calibrated for these applications. Confirm your model and serial number against the fitment table before ordering, as Honda periodically supersedes jets across production runs.
Key Features
- OEM-Calibrated Fuel Metering — the #78 designation is a precise orifice size; this genuine Honda jet delivers the exact fuel flow rate the carburetor was designed around, keeping the air-fuel ratio on specification at wide-open throttle.
- Direct Carburetor Replacement — this jet installs directly into the carburetor's main circuit without modification, restoring original fuel delivery after wear, varnish buildup, or damage has altered the orifice.
- Broad Fitment Across Honda Lineups — listed for GX200, GX240, and GX270 horizontal shaft engines, EB- and EM-series generators, the EU3000 inverter generator, EX3300, and HS724 and HSS724 two-stage snow blowers, including models covering a wide span of production years.
- Serial Number Verification Recommended — Honda supersedes carburetor jets at specific production breaks; check your unit's serial number against the fitment table to confirm part number 99101-ZH8-0780 is correct for your machine before installation.
The main jet is the primary metering component in a float-type carburetor. Fuel is drawn through its precisely sized orifice and mixed with incoming air to form the combustible charge the engine needs at full load. The orifice diameter — indicated here by the #78 designation — is calculated to a tight tolerance; even a small deviation from spec causes a rich or lean condition that shows up as power loss, rough running, excess fuel consumption, or fouled spark plugs. When a main jet becomes clogged with varnish from stale fuel or is damaged during carburetor cleaning, the engine will run lean under load, overheat, and lose power. Installing a correctly sized replacement jet restores the carburetor to its original calibration and brings the engine back to full operating performance.
Part Details
| Part Number | 99101-ZH8-0780 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Main Jet (#78) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Generator | EB3500, EB3800, EB4000, EB5000, EB6500, EM3500, EM3800, EM4000, EM5000, EM6500, EX3300 | All |
| Horizontal Shaft Engine | GX200, GX240, GX270 | All |
| Inverter Generator | EU3000 | All |
| Two-Stage Snow Blower | HS724, HSS724 | 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.
