Part Number: ZWD4035G
Category: Pressure Washer Pumps → Triplex Pumps → Gas Pressure Washer Pumps
Type: Comet ZWD4035G Pressure Washer Pump – 4.0 GPM 3500 PSI 1" Gas Flange

The Comet ZWD4035G Pressure Washer Pump (Part #ZWD4035G) is a genuine OEM triplex plunger pump engineered for demanding commercial and industrial pressure washing applications. Manufactured by Comet Pumps, this heavy-duty direct-drive pump delivers 4.0 GPM at 3,500 PSI, providing exceptional cleaning performance for fleet washing, heavy equipment, construction sites, agricultural operations, manufacturing facilities, and other professional cleaning environments.

Key Features & Benefits

• Genuine Comet OEM triplex pressure washer pump
• Part Number: ZWD4035G
• Heavy-duty triplex plunger design
• Delivers up to 4.0 GPM at 3,500 PSI
• Designed for gas-powered pressure washers
• 1-inch hollow shaft for direct engine mounting
• Operates at 3,400 RPM
• Compatible with engines up to 10.7 GHP
• 15 mm ceramic plungers for extended durability
• 1/2" FPT water inlet
• 3/8" FPT high-pressure outlet
• OEM-quality construction for demanding commercial applications

Technical Specifications

Part Number: ZWD4035G

Pump Model: ZWD4035G

Manufacturer: Comet Pumps

Product Type: Triplex Pressure Washer Pump

Maximum Flow Rate: 4.0 GPM

Maximum Pressure: 3,500 PSI

Maximum Pump Speed: 3,400 RPM

Gas Horsepower (GHP): 10.7

Shaft Size: 1" Hollow Shaft

Ceramic Plunger Size: 15 mm

Water Inlet: 1/2" FPT

High-Pressure Outlet: 3/8" FPT

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

Weight: 17 lbs

OEM Replacement: Yes

Compatible Applications

Designed for use with compatible gas-powered pressure washer systems featuring:

• 1-inch horizontal engine shafts
• Direct-drive pressure washer systems
• Engines up to 10.7 GHP
• Commercial pressure washers
• Industrial cleaning equipment
• Fleet washing systems
• Agricultural equipment cleaning
• Construction equipment cleaning
• Equipment replacement and repair projects
• OEM equipment installations

Always verify shaft size, mounting configuration, engine horsepower, and pressure/flow requirements before ordering.

Function of the Pressure Washer Pump

The ZWD4035G pump helps:

• Deliver up to 4.0 GPM of water flow
• Generate operating pressures up to 3,500 PSI
• Restore pressure washer performance
• Provide powerful cleaning for commercial and industrial applications
• Deliver smooth, efficient pump operation
• Support continuous-duty cleaning performance

Its heavy-duty triplex plunger design provides superior durability, improved efficiency, and longer service life than conventional 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 cleaning performance while minimizing costly equipment downtime.

Installation & Service Notes

• Shut down the pressure washer and disconnect the spark plug before servicing.
• Relieve all system pressure.
• Verify compatibility with the 1-inch shaft, mounting configuration, engine horsepower, and pressure requirements.
• Install the pump according to the manufacturer's specifications.
• Connect the 1/2" FPT inlet and 3/8" FPT outlet fittings.
• 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 service the pump according to Comet maintenance schedules.
• Inspect ceramic plungers, packings, water seals, valves, and fittings during routine maintenance.
• Maintain clean, filtered inlet water to minimize internal wear.
• Flush the pump after use when pumping dirty or corrosive water.
• Use only genuine OEM Comet replacement parts and approved lubricants to maintain optimum pump performance, reliability, and long service life.