Part Number: FW2-3540S
Category: Pressure Washer Pumps → Triplex Pumps → Belt Drive Pressure Washer Pumps
Type: Comet FW2-3540S Pressure Washer Pump – 3.4 GPM 4000 PSI 1450 RPM 31mm Shaft

The Comet FW2-3540S Pressure Washer Pump (Part #FW2-3540S) is a genuine OEM triplex plunger pump engineered for demanding commercial and industrial pressure washing applications. Manufactured by Comet Pumps, this heavy-duty pump delivers 3.4 GPM at 4,000 PSI, providing exceptional cleaning power for fleet washing, construction equipment, industrial facilities, agricultural operations, and other continuous-duty cleaning applications.

Key Features & Benefits

• Genuine Comet OEM triplex pressure washer pump
• Part Number: FW2-3540S
• Heavy-duty triplex plunger design
• Delivers up to 3.4 GPM at 4,000 PSI
• Low-speed 1,450 RPM operation for extended service life
• 31 mm solid shaft
• 18 mm ceramic plungers
• 1/2" FPT water inlet
• 3/8" FPT high-pressure outlet
• Compatible with belt-drive and gear-drive systems
• Requires approximately 9.5 BHP
• Suitable for engines up to 12 GHP
• OEM-quality durability for continuous-duty commercial use

Technical Specifications

Part Number: FW2-3540S

Pump Model: FW2-3540S

Manufacturer: Comet Pumps

Product Type: Triplex Pressure Washer Pump

Maximum Flow Rate: 3.4 GPM

Maximum Pressure: 4,000 PSI

Maximum Pump Speed: 1,450 RPM

Brake Horsepower (BHP): 9.5

Gas Horsepower (GHP): 12

Shaft Size: 31 mm

Ceramic Plunger Size: 18 mm

Water Inlet: 1/2" FPT

High-Pressure Outlet: 3/8" FPT

Connection Size: 1/2" Inlet / 3/8" Outlet

Weight: 20 lbs

OEM Replacement: Yes

Compatible Applications

Designed for use with compatible pressure washer systems featuring:

• 31 mm shaft drive systems
• Belt-drive pressure washers
• Gear-drive pressure washers
• Commercial pressure washers
• Industrial cleaning equipment
• Fleet washing systems
• Agricultural equipment cleaning
• Manufacturing facilities
• Equipment replacement and repair projects
• OEM equipment installations

Always verify shaft dimensions, mounting configuration, horsepower requirements, and pressure/flow specifications before ordering.

Function of the Pressure Washer Pump

The FW2-3540S pump helps:

• Deliver up to 3.4 GPM of water flow
• Generate operating pressures up to 4,000 PSI
• Provide reliable continuous-duty cleaning performance
• Operate efficiently at low pump speeds
• Reduce heat buildup and internal wear
• Extend equipment service life in demanding applications

Its heavy-duty triplex plunger design provides superior durability, smoother operation, and longer service life than high-speed pump designs.

Common Signs Replacement Is Needed

Replace the pump if you notice:

• Reduced operating pressure
• Decreased water flow
• Water or oil leaks
• Excessive operating noise
• Cracked or damaged pump housing
• Excessive internal wear
• Loss of cleaning performance
• Pump failure during operation

Replacing a worn pump restores pressure washer performance while minimizing costly equipment downtime.

Installation & Service Notes

• Shut down the pressure washer and relieve all system pressure.
• Disconnect the engine or motor before servicing.
• Verify compatibility with the 31 mm shaft, mounting configuration, pulley alignment, horsepower requirements, and plumbing connections.
• Install the pump according to the manufacturer's specifications.
• Connect the 1/2" FPT inlet and 3/8" FPT outlet fittings.
• Fill the crankcase with the recommended pump oil before operation if required.
• Prime the pump with water before startup.
• Verify proper operation and inspect for leaks after installation.

Important: Never operate the pump without an adequate water supply. Running the pump dry can quickly damage the ceramic plungers, seals, and valves, significantly reducing pump service life.

Maintenance Recommendations

• Check the pump oil level regularly and change the oil according to Comet maintenance schedules.
• Inspect ceramic plungers, packings, seals, valves, and fittings during routine maintenance.
• Maintain clean, filtered inlet water to minimize internal wear.
• Check belt alignment and belt tension periodically on belt-drive systems.
• Use only genuine OEM Comet replacement parts and approved lubricants to maintain optimum pump performance, reliability, and long service life.