Diaphragm for Solex 40PII-4 carburettor. Porsche 356 / 912

Diaphragm for Solex 40PII-4 carburettor.
This diaphragm is manufactured to match Porsche OEM specifications, used in the carburettor/fuel pump assembly of early Porsche models such as the 356 B/C and 912 (Solex 40 PII-4 systems). This diaphragm ensures correct movement of the pump or fuel-metering circuit, maintaining consistent fuel delivery, avoiding starvation under load, and preserving the original throttle response characteristics. 

Fits:
Porsche 356B / 356C (Model: 1600 S90/SC, CARRERA, 587/1 692/3A) 1960-1965
Porsche 912 1.6L 1965 - 1969 (Engine code: 616/36/37)
Porsche 912 1.6L 1965 - 1969 (Engine code: 616/39/40)

Diagram ref no 64

• Function: Flexes to actuate fuel-pump or carburettor component; maintains consistent fuel flow and pressure
• Position: Inside carburettor body or fuel pump assembly
• Benefits: Exact fit geometry, reliable sealing, restores factory fuel-delivery behaviour
• Installation: Replace during carburettor rebuild or fuel-system service; Ensure correct mounting orientation and inspect surrounding seals/gaskets.

Diaphragms in carburettor or fuel-pump assemblies are subject to continuous flexing, contact with fuel/ vapour, and ageing of elastomer materials. Over time the diaphragm may become hardened, cracked, or leak, leading to inconsistent fuel delivery, hesitation under acceleration or poor idle.

Replace this diaphragm when:
• Performing a carburettor rebuild, fuel-pump service or full engine commissioning
• The existing diaphragm shows visible cracks, deformation, fuel seepage or stickiness
• You experience fuel starvation, erratic throttle response or tuning instability
• You’re restoring your classic Porsche engine to factory-correct performance

Installing a new diaphragm restores correct actuation, sealing and fuel-flow behaviour—ensuring your induction system runs true, smooth and as intended.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

PCG10095100

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