K&N Inline Electric Fuel Pump (81-0400)

The K&N 81-0400 is a specialized, universal inline electric fuel pump designed specifically for vintage and low-pressure carbureted applications. It provides the steady, reliable fuel delivery necessary for classic engines, helping to prevent the common issues associated with mechanical pump failures, such as vapor lock or inconsistent pressure.

Key Specifications

• Part Number: 81-0400
• Flow Rate: 57 Liters per Hour (15 Gallons per Hour)
• Operating Pressure: 1–2 PSI (Self-Regulating)
• Compatibility: Gasoline, Diesel, Biodiesel, E85, Methanol, Ethanol, and Alcohol
• Design Type: External / Inline
• Inlet/Outlet: 5/16" Hose Barb
• Voltage: 12V DC system
• Filtration: Includes required 74-micron in-line fuel filter

Product Overview & Performance

Engineered for low-pressure requirements, the 81-0400 is the ideal choice for engines that require minimal fuel pressure to run smoothly. Its compact, solid-state internal design allows for versatile mounting locations along the fuel line. Being self-priming and self-regulating, it eliminates the need for an external fuel pressure regulator, making it a "set-it-and-forget-it" solution for vintage restorations and classic street builds.

Usage & Application Notes

• Versatility: Broad fuel compatibility makes it suitable for various vintage fuel system requirements.
• Application: Perfect for small-displacement engines, classic motorcycles, and vintage cars requiring low PSI.
• Safety Tip: Mount the pump as close to the fuel tank as possible (within 12 inches vertically) to maximize pump life and ensure consistent priming.

K&N Inline Fuel Pump Series

Compare the K&N fuel pump range to select the ideal flow and pressure for your engine build:

• 81-0400 - 57LPH, 1–2 PSI (Ideal for Vintage & Low-Pressure)
• 81-0401 - 95LPH, 1.5–4 PSI (Street Performance)
• 81-0402 - 121LPH, 4–7 PSI (High-Performance Carbureted)
• 81-0403 - 129LPH, 7–10 PSI (High-Flow / Diesel Capable)