O-ring 25x3.5 FS40, FS40C
SKU: Stihl | ST-9645 948 7734
- Regular price
- £0.58 Ex VAT
- £0.70 Inc VAT
- Sale price
- £0.58 Ex VAT
- Regular price
-
- £0.00 £0.70 Inc VAT
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Product information & specifications
STIHL O-Ring 25 x 3.5 - Genuine OEM Seal Ring
The STIHL O-Ring 25 x 3.5 is a genuine OEM sealing ring designed to provide reliable leak protection in small engine assemblies, fuel systems and fluid connections across a wide range of STIHL outdoor power equipment. Manufactured from durable rubber compound material, this O-ring helps maintain dependable sealing performance under exposure to fuel, oil, vibration and temperature changes commonly found in professional and domestic handheld machinery.
With a precise 25 mm inner diameter and 3.5 mm cross-section, the STIHL O-Ring 25x3.5 fits accurately into matching grooves to support consistent sealing without distortion. The exact dimensions of 25 mm x 3.5 mm help maintain proper pressure retention in housings, caps, carburettor interfaces and line joints. Suitable for equipment including the STIHL FS 40, FS 40 C, MS 261, MS 500i and BR 600, this genuine seal ring helps reduce leaks, supports smoother engine operation and assists with long-term reliability during routine servicing and repairs.
Key Features
- Genuine STIHL OEM O-ring for assured fit and sealing performance
- Size: 25 mm inner diameter x 3.5 mm cross-section
- Durable rubber construction designed for engine and fuel system environments
- Helps prevent fuel, oil and air leaks in compatible assemblies
- Supports reliable starting and smooth engine operation
- Resistant to vibration, heat and outdoor operating conditions
- Accurate dimensions for dependable groove fitment and sealing integrity
- Suitable for chainsaws, trimmers, blowers, hedge trimmers and Kombi tools
- Useful replacement during servicing and preventative maintenance
- Designed for repeatable OEM-quality sealing performance
Typical Applications
This STIHL O-ring is commonly used to seal static and lightly dynamic joints in small engines and handheld outdoor power equipment. Typical uses include fuel system joints, carburettor interfaces, line unions, housing seals, pump seals and cover assemblies where reliable sealing is required to prevent leakage and maintain correct system pressure.
The 25 mm inner diameter and 3.5 mm profile make this seal suitable for many STIHL brushcutters, chainsaws, hedge trimmers, Kombi tools, blowers and cut-off machines operating in forestry, landscaping, grounds maintenance and domestic garden care applications.
Technical Specification
| Brand | STIHL |
|---|---|
| Product Type | O-Ring / Seal Ring |
| Size | 25 mm x 3.5 mm |
| Inner Diameter | 25 mm |
| Cross-Section | 3.5 mm |
| Material | Durable rubber sealing compound |
| Manufacturer Part Number | 9645 948 7734 |
| Alternate Part Numbers | 9645-948-7734, 96459487734 |
Fits Models
Compatible with a wide range of STIHL equipment, including selected:
- STIHL FS 40 & FS 40 C brushcutters
- STIHL FS 56, FS 70 and FS 90 series trimmers
- STIHL KM KombiSystem engines
- STIHL BR 500, BR 550 and BR 600 blowers
- STIHL MS 171, MS 181, MS 261 and MS 500i chainsaws
- STIHL HS hedge trimmers
- STIHL HT pole pruners
- Additional compatible STIHL models listed in manufacturer parts documentation
Also Known As
- Seal ring
- Rubber sealing ring
- Circular gasket
- Round-section seal
- O-ring seal
- Ring gasket
- Fuel system O-ring
Why Choose Genuine STIHL Seals?
Small sealing components play an important role in engine reliability and pressure retention. Genuine STIHL O-rings are manufactured to precise OEM tolerances, helping maintain the correct fit, compression and chemical resistance required for outdoor power equipment exposed to fuel, oil, vibration and varying operating temperatures.
Complete Your Kit
Explore More
FAQs
What size is this STIHL O-ring?
This O-ring has a 25 mm inner diameter and a 3.5 mm cross-section.
What is this O-ring used for?
It is used to seal fuel, oil and air connections in compatible STIHL outdoor power equipment.
Is this a genuine STIHL part?
Yes, this is a genuine STIHL OEM sealing ring designed for compatible STIHL machines.
Which STIHL tools can use this O-ring?
It fits a wide range of STIHL chainsaws, trimmers, hedge trimmers, blowers and Kombi tools.
Why replace a worn O-ring?
Replacing damaged O-rings helps prevent leaks, maintain pressure and support reliable engine performance.
STIHL O-Ring 25 x 3.5 - Genuine OEM Seal Ring
The STIHL O-Ring 25 x 3.5 is a genuine OEM sealing ring designed to provide reliable leak protection in small engine assemblies, fuel systems and fluid connections across a wide range of STIHL outdoor power equipment. Manufactured from durable rubber compound material, this O-ring helps maintain dependable sealing performance under exposure to fuel, oil, vibration and temperature changes commonly found in professional and domestic handheld machinery.
With a precise 25 mm inner diameter and 3.5 mm cross-section, the STIHL O-Ring 25x3.5 fits accurately into matching grooves to support consistent sealing without distortion. The exact dimensions of 25 mm x 3.5 mm help maintain proper pressure retention in housings, caps, carburettor interfaces and line joints. Suitable for equipment including the STIHL FS 40, FS 40 C, MS 261, MS 500i and BR 600, this genuine seal ring helps reduce leaks, supports smoother engine operation and assists with long-term reliability during routine servicing and repairs.
Key Features
- Genuine STIHL OEM O-ring for assured fit and sealing performance
- Size: 25 mm inner diameter x 3.5 mm cross-section
- Durable rubber construction designed for engine and fuel system environments
- Helps prevent fuel, oil and air leaks in compatible assemblies
- Supports reliable starting and smooth engine operation
- Resistant to vibration, heat and outdoor operating conditions
- Accurate dimensions for dependable groove fitment and sealing integrity
- Suitable for chainsaws, trimmers, blowers, hedge trimmers and Kombi tools
- Useful replacement during servicing and preventative maintenance
- Designed for repeatable OEM-quality sealing performance
Typical Applications
This STIHL O-ring is commonly used to seal static and lightly dynamic joints in small engines and handheld outdoor power equipment. Typical uses include fuel system joints, carburettor interfaces, line unions, housing seals, pump seals and cover assemblies where reliable sealing is required to prevent leakage and maintain correct system pressure.
The 25 mm inner diameter and 3.5 mm profile make this seal suitable for many STIHL brushcutters, chainsaws, hedge trimmers, Kombi tools, blowers and cut-off machines operating in forestry, landscaping, grounds maintenance and domestic garden care applications.
Technical Specification
| Brand | STIHL |
|---|---|
| Product Type | O-Ring / Seal Ring |
| Size | 25 mm x 3.5 mm |
| Inner Diameter | 25 mm |
| Cross-Section | 3.5 mm |
| Material | Durable rubber sealing compound |
| Manufacturer Part Number | 9645 948 7734 |
| Alternate Part Numbers | 9645-948-7734, 96459487734 |
Fits Models
Compatible with a wide range of STIHL equipment, including selected:
- STIHL FS 40 & FS 40 C brushcutters
- STIHL FS 56, FS 70 and FS 90 series trimmers
- STIHL KM KombiSystem engines
- STIHL BR 500, BR 550 and BR 600 blowers
- STIHL MS 171, MS 181, MS 261 and MS 500i chainsaws
- STIHL HS hedge trimmers
- STIHL HT pole pruners
- Additional compatible STIHL models listed in manufacturer parts documentation
Also Known As
- Seal ring
- Rubber sealing ring
- Circular gasket
- Round-section seal
- O-ring seal
- Ring gasket
- Fuel system O-ring
Why Choose Genuine STIHL Seals?
Small sealing components play an important role in engine reliability and pressure retention. Genuine STIHL O-rings are manufactured to precise OEM tolerances, helping maintain the correct fit, compression and chemical resistance required for outdoor power equipment exposed to fuel, oil, vibration and varying operating temperatures.
Complete Your Kit
Explore More
FAQs
What size is this STIHL O-ring?
This O-ring has a 25 mm inner diameter and a 3.5 mm cross-section.
What is this O-ring used for?
It is used to seal fuel, oil and air connections in compatible STIHL outdoor power equipment.
Is this a genuine STIHL part?
Yes, this is a genuine STIHL OEM sealing ring designed for compatible STIHL machines.
Which STIHL tools can use this O-ring?
It fits a wide range of STIHL chainsaws, trimmers, hedge trimmers, blowers and Kombi tools.
Why replace a worn O-ring?
Replacing damaged O-rings helps prevent leaks, maintain pressure and support reliable engine performance.
Delivery & Returns
UK Delivery
Fast, reliable delivery from our UK warehouse.
- FREE UK Standard Delivery
applies to eligible UK orders over £75 ex VAT.
Estimated delivery: 2–4 working days
- UK Standard Delivery from £3.60 + VAT
Estimated delivery: 2–4 working days
- Next Working Day Delivery – £6.00 + VAT
Order before 3:00pm (Monday–Friday) for next working day delivery
All UK orders are dispatched Monday–Friday and sent via a tracked courier service.
International Delivery
We ship worldwide from the UK.
- Europe from £10.00
Estimated delivery: 2–7 working days - Rest of the World from £12.00
Estimated delivery: 2–11 working days
Shipping costs and delivery times are calculated at checkout based on destination and order contents.
Customs, Duties & Taxes
International orders may be subject to local import duties, taxes, or customs charges.
When UPS is selected at checkout, applicable duties and taxes are included in the total price. For other shipping services, duties and taxes may be charged separately on delivery and are the responsibility of the recipient.
Customs processing times may affect delivery estimates.
Returns
30-Day Return Policy
- Items can be returned within 30 days of delivery
- Products must be unused and in original condition
- Return postage costs apply unless the item is faulty or incorrect
For full details, please visit our Shipping & Returns page.
UK Delivery
Fast, reliable delivery from our UK warehouse.
- FREE UK Standard Delivery
applies to eligible UK orders over £75 ex VAT.
Estimated delivery: 2–4 working days
- UK Standard Delivery from £3.60 + VAT
Estimated delivery: 2–4 working days
- Next Working Day Delivery – £6.00 + VAT
Order before 3:00pm (Monday–Friday) for next working day delivery
All UK orders are dispatched Monday–Friday and sent via a tracked courier service.
International Delivery
We ship worldwide from the UK.
- Europe from £10.00
Estimated delivery: 2–7 working days - Rest of the World from £12.00
Estimated delivery: 2–11 working days
Shipping costs and delivery times are calculated at checkout based on destination and order contents.
Customs, Duties & Taxes
International orders may be subject to local import duties, taxes, or customs charges.
When UPS is selected at checkout, applicable duties and taxes are included in the total price. For other shipping services, duties and taxes may be charged separately on delivery and are the responsibility of the recipient.
Customs processing times may affect delivery estimates.
Returns
30-Day Return Policy
- Items can be returned within 30 days of delivery
- Products must be unused and in original condition
- Return postage costs apply unless the item is faulty or incorrect
For full details, please visit our Shipping & Returns page.