Kawasaki FX801V-NS00-S 25.5HP V-Twin Vertical Shaft Engine Electric Start

Kawasaki FX801V-NS00-S 25.5HP V-Twin Vertical Shaft Engine Electric Start

When serious work calls for serious power, the Kawasaki FX801V engine dials up the delivery for top-of-the-line strength and dependable durability. This V-twin 4-cycle vertical shaft engine features cast-iron cylinders, metal engine cover, heavy-duty shift-type starter, and high-efficiency oil cooler for performance that powers through.

Features: 

Engine performance, by the numbers.

• From power and torque numbers to engine features and more, the following is here to help communicate engine performance details and capabilities. Be sure to consider these specs to help ensure the engine you’re choosing is a match to your mowing needs.

Overhead v-valve

• The Kawasaki FX801V-NS00-S utilizes an advanced Overhead V-Valve (OHV) architecture, a precision-engineered design that places the valves directly above the 852cc combustion chambers in a high-efficiency V-configuration. This layout optimizes the engine's volumetric efficiency, allowing for smoother airflow and more complete fuel combustion to extract maximum power from every stroke. By centralizing the spark plug and streamlining the intake and exhaust paths, the OHV design ensures that this 25.5HP engine maintains superior thermal stability and high-torque recovery, providing the consistent "Critical Power" required to drive large commercial mower decks through the most challenging turf conditions.

90° V-twin

• The Kawasaki FX801V-NS00-S is built on a 90° V-Twin architecture, an industry-leading configuration renowned for providing perfect mechanical balance and professional-grade smoothness. By arranging the cylinders at a precise 90-degree angle, this 852cc engine naturally cancels out primary vibrations, significantly reducing operator fatigue and protecting the mower’s frame and belts from harmonic stress. This synchronized firing sequence delivers a continuous, high-torque power flow to the blades, ensuring that the 25.5HP output remains steady and unfaltering even when the engine is subjected to the sudden, heavy loads of commercial landscaping.

Pressurized lubrication system

• The Kawasaki FX801V-NS00-S is engineered with a high-performance pressurized lubrication system, an automotive-grade oiling architecture designed to safeguard your engine under the most grueling commercial conditions. Unlike standard splash systems, this setup utilizes a dedicated high-volume pump to force a constant stream of filtered oil directly to the 852cc engine's critical crankshaft and rod bearings, ensuring total protection even when operating at high speeds or on steep 20-degree inclines. By pairing this consistent oil flow with a premium spin-on filter to trap microscopic contaminants, the system significantly reduces internal friction and heat, providing the "Critical Power" and industrial-strength longevity required for a 25.5HP engine to survive back-to-back professional mowing seasons.

Electronic spark ignition

• The Kawasaki FX801V-NS00-S is equipped with a high-output electronic spark ignition, a state-of-the-art solid-state system designed to provide maintenance-free starting and precision-timed performance. By utilizing digital ignition timing, this system ensures the 25.5HP engine fires up instantly and reliably in all weather conditions, while delivering a more powerful and consistent spark compared to traditional mechanical ignitions. This optimized combustion process allows the 852cc V-Twin to achieve superior fuel efficiency and smoother power delivery across its entire RPM range, ensuring the engine remains responsive and dependable throughout the most demanding commercial workdays.

Automatic compression release

• The Kawasaki FX801V-NS00-S features an integrated mechanical automatic compression release (ACR), a precision-engineered system designed to provide effortless, "turn-key" starting for this high-displacement power plant. By intelligently venting a portion of the cylinder pressure during the initial cranking phase, the ACR significantly reduces the torque required to turn the 852cc engine, drastically lowering the electrical strain on the battery and starter motor. Once the engine fires and reaches a specific RPM, the system automatically disengages to allow for full 25.5HP combustion, ensuring an instant, low-strain start every time while extending the service life of your equipment's entire electrical system.

High efficiency oil cooler

• The Kawasaki FX801V-NS00-S is outfitted with a high-efficiency oil cooler, an essential thermal management feature designed to maintain peak performance during grueling commercial shifts. This external, automotive-style heat exchanger significantly lowers the temperature of the engine oil before it is recirculated through the 852cc block, preventing the fluid from thinning out or breaking down under extreme heat. By keeping the lubricant within its optimal viscosity range, the cooler ensures that every internal component of the 25.5HP engine remains fully protected, effectively extending the service life of the oil and providing the cooling capacity necessary for all-day operation in the most punishing summer conditions.

Rotating metal grass chopper screen

• The Kawasaki FX801V-NS00-S features a rotating metal grass chopper screen, a rugged, active debris-management system built for the harsh realities of commercial mowing. As the engine runs, this heavy-duty screen spins at high velocity, using centrifugal force to launch grass clippings and organic matter away from the air intake before they can clog the cooling fins. Unlike static plastic guards, the "chopper" design physically shreds larger debris to maintain an unobstructed flow of cool air to the 852cc block. This self-cleaning action prevents power-robbing heat spikes and eliminates the need for frequent manual cleaning, ensuring the 25.5HP engine stays thermally stable during long, dusty shifts in the field.

Multi-Stage canister air filter

• This dual-element design features a primary high-capacity filter and a secondary safety element housed within a rugged, heavy-duty canister, effectively trapping microscopic dust and abrasive particles before they can enter the 852cc combustion chamber. By offering significantly greater surface area and a higher debris-holding capacity than standard residential filters, this multi-stage system ensures that the 25.5HP V-Twin breathes clean, cool air even during all-day operation in extremely dry and dusty conditions, dramatically extending the service life of internal components and reducing overall maintenance frequency.

Cast-iron cylinder liners

• While standard engines often use softer aluminum bores, these high-strength iron sleeves are designed to withstand the intense friction and extreme thermal stress generated by the 852cc block during all-day operation. This industrial-grade architecture not only ensures the 25.5HP engine maintains consistent compression and oil retention over thousands of hours, but it also provides the structural integrity needed to resist scuffing and scoring, guaranteeing long-term reliability for professional landscaping crews.

Metal engine cover with integrated clean out ports

• This heavy-duty steel housing provides superior impact resistance compared to standard plastic covers, shielding the 852cc engine's sensitive components from low-hanging branches and flying debris. To ensure consistent cooling performance, the cover features strategically placed, tool-free access ports that allow operators to quickly blow out trapped grass and chaff from the cooling fins during routine maintenance. This thoughtful design ensures your 25.5HP engine remains free of debris-related hotspots, maintaining peak thermal efficiency throughout the most demanding workweeks.

Heavy duty shift-type starter

• Unlike standard starters that use a simpler bendix gear, this high-torque solenoid system physically "shifts" the drive gear into full engagement with the flywheel before the motor begins to spin. This precise, positive engagement prevents gear clashing and ensures the 852cc engine fires up instantly and reliably, even on cold mornings or after short-cycling during frequent stops. By delivering the massive cranking power needed to turn a 25.5HP V-Twin, this industrial starter minimizes mechanical wear and provides the "turn-key" dependability required by professionals who can’t afford downtime.