Products Description
Chainsaw Oil Seal – Crankshaft Seal Replacement Guide
Sealing Component for 2-Stroke Chainsaw Engines
The oil seal (also known as a crankshaft seal) is a critical component that prevents lubricant from leaking out of the engine and keeps dirt and debris from entering the crankcase . These seals are located on the crankshaft where it exits the engine housing on both the flywheel/magneto side and the clutch/PTO side. Over time, oil seals can harden, crack, or wear out, leading to oil leaks, air leaks, and engine performance issues. Replacing worn seals is essential for maintaining proper crankcase pressure and preventing lean running conditions that can cause engine seizure.
Technical Profiles & Materials
Prevents Oil Leaks – Ensures a tight seal around the crankshaft to maintain proper lubrication and prevent oil leakage, keeping the engine clean and operating efficiently .
Protects Internal Components – Shields bearings and internal parts from dirt and debris, reducing wear and contamination .
Precision Fitment – Manufactured to exact OEM specifications for specific chainsaw models, with dimensions varying by brand and engine platform (e.g., 15x26x5mm, 17x30x4.4mm, or 15x25x5mm) .
Durable Material – Made from oil-resistant rubber compounds designed to withstand heat, pressure, and rotation .
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Function | Crankshaft sealing, oil leak prevention |
| 2 | Common Sizes | 15x26x5mm, 15x25x5mm, 17x30x4.4mm |
| 3 | Material | Oil-resistant rubber |
| 4 | Installation Position | Flywheel side & Clutch/PTO side |
| 5 | Typical OEM Cross-Reference | 505275719 (Husqvarna), 96380031581 (Stihl), V505000011 (Echo) |
| 6 | Replacement Indicator | Visible oil leaks, hard starting, erratic idle |
Products Application
Oil Leak Repair
Direct replacement when visible oil seepage is present around the crankshaft area. Worn seals allow oil to escape, leading to low oil levels and potential engine damage. A failed seal can also allow air to enter the crankcase, causing hard starting and erratic idling.
Engine Overhaul & Rebuild
When performing a full engine rebuild or replacing bearings, oil seals should always be renewed. Rebuild kits often include both oil seals along with bearings and gaskets for complete restoration .
Preventative Maintenance
Replacing oil seals proactively during routine servicing prevents unexpected failures and extends engine life. This is especially important for professional-use chainsaws with high operating hours.
Quality and Craftsmanship Details
Products Package
About Us
As a premier garden machinery parts supplier, Jiaxing Norsun Trading Co., Ltd. bridges global distributors with over 100 vetted China manufacturers. We streamline your B2B supply chain through strict quality control, flexible production, and factory-direct wholesale pricing. Partner with us for reliable, high-volume sourcing of precision-engineered outdoor power equipment components.
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FAQ
Q: How do I confirm which oil seal fits my chainsaw?
A:Check your chainsaw model number and refer to OEM part numbers. Common cross-references include Husqvarna 505275719, STIHL 96380031581, and Echo V505000011 . Measure the shaft diameter and housing bore if unsure.
Q: What are the symptoms of a worn oil seal?
A: Common symptoms include visible oil leaks around the crankshaft, hard starting, erratic idling, and lean running conditions. If left unaddressed, a failed seal can cause engine seizure due to air leaks affecting the fuel-air mixture.
Q: Are oil seals sold individually or in sets?
A: Both options are available. Seals can be purchased individually or as part of complete rebuild kits that include bearings, seals, and other components .
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