Name: Hitachi 6684693 Pump Diaphragm
Brand: Hitachi
SKU: 6684693
Price: 5.16 GBP
Availability: InStock

Hitachi 6684693 Spare Part - Pump Diaphragm

Hitachi part 6684693 — Pump diaphragm (original Hitachi) for small two-stroke outdoor engines. This flexible rubber diaphragm seals and flexes inside the carburetor/priming pump assembly to move fuel from the tank into the carburetor; it’s the exact diaphragm used in Hitachi/Metabo HPT/Tanaka engine pump assemblies.

Why this part matters: a worn or cracked diaphragm causes poor fuel delivery, hard starting, stalling or loss of power. The 6684693 is supplied as the single pump diaphragm (part code HIT-6684693) and replaces older Hitachi reference numbers such as 576-25100-20 and 6696325.

Example models this diaphragm fits (representative list): CH66EB3, CH62EA3, CH55EB3, CH50EA3, CG24EAP / CG24EKSL series, RB65EF, TRB24EAP, TRB27EAP and various THB/TBL backpack blower and trimmer engines that use the same pump assembly. Confirm by matching your model’s carburetor / pump exploded view to part 6684693.

Quick practical notes for the repair: the diaphragm is a thin, flexible rubber component that sits against the pump body and diaphragm cover; replace it along with the pump gasket and inlet screen if they show wear to restore reliable fuel flow. It’s sold individually and ships as the genuine Hitachi replacement diaphragm.

If you need the exact fit for your model, match your tool’s part diagram to part number 6684693 (often listed under “pump diaphragm” or “priming diaphragm” in Hitachi parts diagrams).

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