0435957 Evinrude Johnson Diaphragm Cup AY | Genuine OEM BRP Outboard Part

🔧 Product Description

Genuine BRP Evinrude Johnson Thermostat Diaphragm and Cup Assembly - Part Number: 0435957

A genuine BRP diaphragm-and-cup assembly for the thermostat and pressure-control cooling system used on selected Evinrude and Johnson two-stroke outboards.

The flexible diaphragm responds to cooling-water pressure and works with the thermostat, spring and valve components to control bypass flow through the engine.

⚙️ Key Features

• Genuine BRP OEM thermostat diaphragm assembly

• Correct OEM part number 0435957

• Common unprefixed number 435957

• Combined flexible diaphragm and supporting cup

• Used in pressure-controlled cooling systems

• Sierra, GLM and Recmar alternatives available

🔄 Supersession & Cross Reference

OEM / Related Numbers:

• 0435957

• 435957

• 0437352

• 437352

• 0437694

• 437694

• 0336184

• 336184

• OEM Description: Diaphragm and Cup Assembly

• Alternate Description: Thermostat Diaphragm Assembly

Aftermarket / Verified Equivalents:

• Sierra: 18-3501

• GLM: 46132

• Recmar: REC435957

• Aftermarket thermostat diaphragm replacing 0435957

• Outboard Spares reference: OSD435

🚤 Compatibility

Commonly used on selected:

• 8HP engines

• 9.9HP and 15HP: approximately 1993-2005

• Three-cylinder 25HP-35HP: approximately 1996-2001

• 40HP and 50HP: approximately 1995-2001

• Three-cylinder 60HP and 70HP: approximately 1993-2001

• 120HP and 140HP: approximately 1993-2001

• 130HP: approximately 1995-2000

• 135HP: selected 2001 applications

Important fitment note:

• The diaphragm is part of the cooling system, not a fuel-pump diaphragm.

• Cooling-system designs vary substantially between otherwise similar horsepower models.

• Confirm the engine model and cylinder-crankcase diagram.

• Thermostat, spring, valve and cover are separate components unless shown.

🔌 Function

The diaphragm reacts to water-pump pressure and helps regulate cooling-water bypass flow.

Common signs of wear or failure:

• Diaphragm is split or perforated

• Rubber has become hard or distorted

• Cup is cracked

• Engine overheats at low speed

• Cooling-water pressure is unstable

• Engine runs excessively cold at higher speed

• Uneven cylinder-head temperature

• Water leaks from the thermostat cover

Installation considerations:

• Inspect the diaphragm on both sides

• Confirm the cup is installed in the correct orientation

• Check the thermostat and pressure-control spring

• Clean salt from the valve cavity

• Replace cover seals and gaskets

• Tighten the cover evenly

• Confirm water flow and operating temperature after installation

📦 Condition

• Genuine BRP Evinrude Johnson OEM part

• Brand new

• Supplied in genuine or equivalent protective packaging