Honda 16013-Z0H-003 Metering Diaphragm Assembly

The Honda 16013-Z0H-003 Metering Diaphragm Assembly is a genuine OEM component designed for GX25, GX35, and GX50 horizontal shaft engines, the FG110 tiller, HHT25, HHT35, UMC425, and UMC435 trimmers, and the WX10 water pump. As a direct Honda OEM part, it is manufactured to the same specification as the original — ensuring the fuel metering circuit in your carburetor operates exactly as intended. Verify your machine's serial number against the fitment table before ordering, as Honda supersedes carburetor components at serial breaks across this range.

Key Features

• Precise Fuel Metering — genuine OEM construction ensures the diaphragm flexes to spec, delivering consistent fuel flow to the carburetor and preventing the rich or lean running conditions a fatigued or cracked diaphragm causes
• Direct OEM Replacement — this assembly drops in where the original sits, with no adaptation needed to restore correct carburetor function
• Broad Fitment — covers GX25, GX35, and GX50 horizontal shaft engines, the FG110 tiller, HHT25, HHT35, UMC425, and UMC435 trimmers, and the WX10 water pump; confirm your serial number against the fitment table to identify the correct application
• Serial-Range Awareness — Honda revises small-engine carburetor assemblies at production breaks, so always match your machine's serial number to the fitment table before purchase

The metering diaphragm is the flexible membrane at the heart of a diaphragm-type carburetor. It responds to engine vacuum to regulate the flow of fuel into the carburetor's metering chamber, maintaining the correct air-to-fuel mixture across varying throttle positions and load conditions. When the diaphragm stiffens, cracks, or develops pinholes with age or fuel exposure, the engine loses the ability to meter fuel accurately — resulting in hard starting, rough idling, hesitation under load, or an engine that stalls and refuses to restart. Replacing this assembly with part number 16013-Z0H-003 restores the carburetor's ability to deliver a consistent, controlled fuel supply and returns the engine to normal operation.

Part Details

Compatibility & Fitment

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.