Products Description
MS661 Chainsaw Oil Pump | Automatic Adjustable-Output Chain Lubrication Pump for Stihl MS 661 & MS 661 C-M Professional Chainsaws
Die-Cast Alloy Oil Pump Assembly with Brass-Bushed Drive Mechanism, Clutch-Driven Variable Output & Precision-Machined Pump Plunger
MS661 Chain saw Oil pump
This automatic oil pump assembly is the chain lubrication delivery system for the Stihl MS 661 and MS 661 C-M - Stihl's 91.1 cc professional-grade chainsaw platform used in commercial forestry, large-scale tree felling, and heavy-duty cross-cutting operations. The pump draws bar and chain oil from the tank reservoir and meters it onto the guide bar and cutting chain at a rate proportional to engine speed: more RPM equals more oil flow, ensuring adequate lubrication when the chain is cutting at full speed and reducing oil consumption at idle.The pump body is die-cast from lightweight aluminum or magnesium alloy with a matte grey textured surface and precision-machined sealing faces. It mounts to the engine crankcase adjacent to the clutch, with the pump drive mechanism engaging the clutch drum. The brass-bushed drive interface provides a low-friction, wear-resistant bearing surface for the rotating pump element, while the machined cylindrical pump plunger - the dark protrusion at the bottom - generates the oil delivery pressure through a reciprocating stroke.
Technical Profiles & Materials
Die-Cast Alloy Body - Lightweight with Precision Sealing Faces：
The pump housing is manufactured from die-cast aluminum or magnesium alloy, chosen for the combination of light weight (important on a chainsaw where every gram matters) and the dimensional stability needed for the precision-machined oil passages and sealing surfaces. The pump must seal against the crankcase without an external gasket - the machined face provides the flat, smooth surface required for metal-to-metal or O-ring sealing against pressurized oil.
Machined Pump Plunger - Positive-Displacement Oil Delivery：
The dark cylindrical protrusion at the bottom of the pump is the machined plunger/piston that generates oil pressure through a reciprocating stroke. As the pump drive rotates, a cam or eccentric mechanism converts rotary motion into a reciprocating push-pull stroke of the plunger, which draws oil from the tank on the intake stroke and pushes it to the bar oil delivery port on the output stroke.
Technical Specifications
| ITEM | DETAILS |
| Type | Automatic Chain Oil Pump Assembly - Clutch-Driven Variable Output |
| Application | Stihl MS 661 & MS 661 C-M professional chainsaws (91.1 cc), bar & chain lubrication oil delivery system |
| Code | 0102256 |
| Material | Die-cast aluminum/magnesium alloy body, sintered bronze bushing, machined steel pump plunger |
| Details explanation | Clutch-driven automatic oil pump. RPM-proportional variable output. Brass-bushed drive interface. Precision-machined sealing faces. Direct bolt-on OEM replacement for Stihl MS 661. |
| Brand Name | SeaSummer |
| Operating Temp | −20 ~ +100 °C (pump body / oil) |
| Delivery Time | 30 Days |
| Packaging | Cardboard packaging |
Products Application
Stihl MS 661 Professional Felling & Bucking Saws
The MS 661 (91.1 cc, 5.4 kW) is Stihl's large-frame professional chainsaw, designed for felling mature hardwood trees, large-scale cross-cutting, and primary timber processing. It runs guide bars from 40 cm to 90 cm (16–36 inches). At these bar lengths, the chain oil pump must deliver sufficient oil volume to lubricate the full length of the bar and chain - a 90 cm bar running at full cutting speed requires significantly more oil than a 40 cm bar. The pump's RPM-proportional output automatically adjusts delivery to match the chain speed and bar length demand, provided the pump is functioning correctly. A pump delivering reduced output on a long bar causes the chain to overheat.
Arborist & Professional Forestry Operations
For tree service companies, commercial logging operations, and municipal forestry crews running MS 661 saws daily, the oil pump is a wear component with a finite service life. The brass-bushed drive mechanism and the plunger bore both wear progressively over hundreds of operating hours, resulting in gradually decreasing oil output. The first symptom is usually the operator noticing the chain looks dry after a cut, or the oil tank level dropping more slowly than expected between refills. Proactive pump replacement at the first sign of reduced output prevents the cascade of bar, chain, and sprocket damage that follows from running a saw with inadequate chain lubrication.
Chainsaw Rebuild & Major Service
During a major chainsaw service - typically performed when the saw is torn down for a piston and cylinder replacement, crankshaft bearing replacement, or clutch replacement - the oil pump is a recommended replacement item. Accessing the pump requires removing the clutch and clutch drum, operations that are already performed during a major teardown. Replacing the pump during this service while the saw is already disassembled eliminates the labor cost of a separate oil-pump-only repair later. For professional saws that log 500–1,000+ operating hours per year, this preventive replacement strategy minimizes unscheduled downtime during the critical felling and processing season.
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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FOR 10000+ OUALITY PARTS
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FAQ
Q: Are you an impartial industrial components dealer or a direct China water pump factors factory?
A:We are a direct, ISO9001-certified engineering water pump components manufacturing facility and precision fluid-control factor manufacture exporter primarily based in China. We function our personal cleanroom injection molding bays, computerized ultrasonic welding arrays, computerized hydraulic stress check stations, and clean-room packaging lines, passing direct-factory wholesale price financial savings straight to your element procurement margins.
Q: Can your manufacturing unit furnish full certification forms for food-contact or consuming water compliance?
A: Yes, absolutely. For food, beverage, or scientific applications, our manufacturing unit makes use of one hundred percent virgin, un-recycled polypropylene resins accompanied by means of fabric traceability certificates. We mechanically furnish B2B purchasers with complete FDA compliance documentation, NSF-grade compound declarations, and RoHS/REACH chemical protection screening sheets to make certain clean clearance thru worldwide customs.
Q: Do you provide customization picks for distinctly corrosive fluids like sturdy acids or ozone?
A: Yes, we are a thoroughly succesful OEM/ODM supplier. For aggressive chemical or ozone environments, we can improve the 12x26.5mm valve configuration in our factory: substituting the general PP housing with top class PVDF (Fluoropolymer) and changing any steel springs with Hastelloy or whole springless gravity-ball architecture, making sure final chemical resistance.
Q: How do we impervious a pattern batch to execute computerized lifecycle and burst-pressure testing?
A: We relatively inspire complete laboratory contrast earlier than logging mass grant agreements. We can ship a pattern lot of 5-10 gadgets of our inventory 12x26.5mm take a look at valves for assessment (setup costs and DHL/FedEx air freight apply). Once the factors pass by your inner lifecycle verification and a formal wholesale quantity manufacturing contract or container run is locked in, the sampling charges are a hundred percent credited returned to your industrial balance.
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