91356-SD4-953 Honda Marine O-Ring | Genuine OEM Outboard Part

🔧 Product Description

Genuine Honda Marine Thermostat O-Ring - Part Number: 91356-SD4-953

Genuine Honda 31.5 × 2.4mm thermostat sealing O-ring used primarily on selected BF75A and BF90A outboards. This NOK-supplier version seals the thermostat-cover joint against cooling-water leakage.

⚙️ Key Features

• Genuine Honda Marine replacement seal
• Nominal dimensions: 31.5mm × 2.4mm
• NOK supplier-coded version
• Designed for thermostat and cooling-water housings
• Recommended replacement whenever the thermostat cover is removed

🚤 Compatibility

Commonly used on

• Honda BF75 and BF90 thermostat assemblies
• Cooling-water housing joints

Typically suits

• Engine models:
• BF75A family
• BF90A family
• Selected BF75AT and BF90AT configurations
• HP Range: 75HP-90HP
• Engine Type: Inline-four four-stroke outboards
• Year Range: Approximately 1997-2006
• Serial Note: Confirm whether the parts diagram specifies the NOK 953 version or the ARAI 952 version for the engine serial.

🔌 Function

The O-ring seals the thermostat cover and prevents cooling water escaping from the housing.

⚠️ Common Signs of Failure

• Water seepage near the thermostat cover
• White salt deposits around the housing
• Corrosion beneath the thermostat cover
• Irregular cooling-system pressure
• Brittle, compressed or damaged seal

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 91356-SD4-953 (documented Honda supplier-specific reference)

OEM / Related Numbers

• 91356SD4953
• 91356-SD4-952 — same nominal size with alternate ARAI supplier designation
• Seal size reference: 31.5 × 2.4mm

Aftermarket / Verified Equivalents

• No aftermarket equivalent

📦 Condition

• Genuine Honda Marine part
• Brand new
• Supplied in original or equivalent protective packaging