The Multiquip 991011240780 Main Jet #78 J-4HC- is a genuine OEM carburetor main jet designed for J-4HC series equipment. Sourced directly from Multiquip, this part meets the exact specifications required for proper fuel metering in the carburetor. It is a direct OEM replacement confirmed for J-4HC series machines, ensuring your equipment runs at the correct air-fuel ratio without guesswork or modification.
Key Features
- Exact OEM Jet Sizing — Calibrated to the #78 orifice specification, ensuring accurate fuel delivery and consistent engine performance.
- Genuine Multiquip OEM Part — Manufactured to the same tolerances as the original, maintaining proper carburetor function and fuel atomization.
- Direct Fit for J-4HC Series — Confirmed fitment for J-4HC equipment; threads and dimensions match the original carburetor housing exactly.
- Consistent Engine Tuning — A correctly sized main jet keeps the engine operating in its designed fuel-to-air range, preventing rich or lean running conditions.
- Part Number 991011240780 — Use this number to cross-reference against your equipment's parts manual for confident ordering.
The main jet is a precision-machined component inside the carburetor that controls the volume of fuel delivered to the engine at mid to full throttle. The small calibrated orifice — rated #78 in this application — meters fuel flow at the correct rate for the engine's air intake. When a main jet becomes clogged, worn, or is replaced with an incorrect size, the engine may run lean, causing overheating and power loss, or run rich, leading to fouled plugs and excessive fuel consumption. Replacing a worn or damaged jet with the correct OEM specification restores proper combustion and protects engine longevity.
Part Details
| Part Number | 991011240780 |
|---|---|
| Brand | Multiquip |
| Part Type | Genuine OEM |
| Description | Main Jet #78 J-4HC-0639831 |
Compatibility & Fitment
| Name | Model |
|---|---|
| J-4HC- | J-4HC- |
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.
