Tillotson 237-604 Metering Diaphragm for HU Series Carburetors

The Tillotson 237-604 is an OEM genuine metering diaphragm designed specifically for Tillotson HU Series carburetors. This critical component plays a vital role in the carburetor's fuel delivery system, ensuring proper engine performance across all operating conditions.

Function and Operation:

The metering diaphragm is subjected to engine suction on the metering chamber side and atmospheric pressure on the vented side. When the engine creates suction, atmospheric air pressure on the opposite side forces the main diaphragm upward, causing the diaphragm button to depress the inlet control lever and permit fuel to enter the fuel chamber. This precise fuel metering system allows the carburetor to function properly at all tilt angles without fuel spilling or flooding.

Key Features:

• Genuine OEM Tillotson replacement part
• Designed for Tillotson HU Series carburetors
• Precise fuel metering control
• Enables proper carburetor operation at all angles
• Essential for maintaining optimal engine performance

Applications:

The HU series carburetor is a miniature all-position diaphragm carburetor that is lightweight and compact, only 1-1/8 inch cube, and includes a self-contained fuel pump and filtering screen. This diaphragm is commonly found in small engine applications including chainsaws, trimmers, and other handheld power equipment using Tillotson HU Series carburetors.

Replacement Information:

This is a critical wear component that should be replaced during carburetor rebuilds or when troubleshooting fuel delivery issues such as flooding, poor idle, or difficulty starting. Aftermarket equivalents include Rotary part number 8155.