Johnson Pump First Mate Bilge Pump 400 GPH, JP-21405, 12V 3/4 Inch Discharge

The Johnson Pump First Mate Bilge Pump JP-21405 is a 400 GPH, 12-volt submersible bilge pump built specifically for pontoon livewell and personal watercraft (PWC) bilge applications, where mounting space is tight and easy maintenance matters. The pump's electric motor can be locked into three different positions, giving installers flexibility to route wiring more directly and work around cramped compartments. It is also extremely tolerant of low battery voltage situations, drawing more amperage from its DC motor as needed to keep pumping rather than stalling out when voltage sags.

An easy-to-plumb 90 degree Dura Port simplifies hose routing through tight spaces, and an integrated side mounting bracket makes installation straightforward without extra hardware. The JP-21405 serves as a direct replacement for older model Mayfair First Mate bilge pumps, so it can be swapped into existing setups built around that earlier design. With a 3/4 inch discharge connection, a 2.5 amp draw, and a recommended 5 amp fuse, this pump is sized for smaller livewell and bilge compartments rather than high-volume bilge duty.

Specifications

• Brand: Johnson Pump
• Manufacturer Part Number: JP-21405
• Type: Bilge Pump
• Style: Manual
• Flow Rate: 400 GPH
• Voltage: 12 V
• Amperage Draw: 2.5 A
• Recommended Fuse Size: 5 A
• Connection / Hose Size: 3/4 inch
• Max Height (Shut-Off Head): 4 inches (100 mm)
• Material: Plastic
• Weight: 0.7 pounds

Fitment

• Pontoon livewell applications
• PWC (personal watercraft) bilge applications
• Direct replacement for older model Mayfair First Mate bilge pumps

Frequently Asked Questions

What is the Johnson Pump JP-21405 designed for? The Johnson Pump First Mate Bilge Pump JP-21405 is built specifically for pontoon livewell and PWC (personal watercraft) bilge applications where mounting space is limited.

What is the flow rate of this bilge pump? The JP-21405 has a flow rate of 400 GPH at 12 volts, with a 2.5 amp draw and a recommended 5 amp fuse.

What size hose connection does it use? This pump has a 3/4 inch discharge connection and uses a 90 degree Dura Port to simplify hose routing in tight spaces.

Will this pump work if my battery voltage is low? Yes, the JP-21405 is extremely tolerant of low battery voltage situations. Its DC motor increases amperage draw as needed to keep operating rather than stalling.

Can this pump replace my old Mayfair bilge pump? Yes, the Johnson Pump JP-21405 is a direct replacement for older model Mayfair First Mate bilge pumps.

How is the JP-21405 mounted? This bilge pump includes an integrated side mounting bracket, and its electric motor can be locked into three different positions to allow more direct wiring routing.

What is the maximum lift height for this pump? The JP-21405 has a maximum height (shut-off head) rating of 4 inches (100 mm).

What material is the pump housing made of? The Johnson Pump First Mate Bilge Pump JP-21405 is constructed of plastic.

What fuse size should I use with this pump? A 5 amp fuse is recommended for the JP-21405, which draws 2.5 amps during operation.

How much does the JP-21405 weigh? The Johnson Pump First Mate Bilge Pump JP-21405 weighs 0.7 pounds.

Is this pump suitable for high-volume bilge duty? No, the JP-21405 is sized for smaller livewell and PWC bilge compartments rather than high-volume bilge pumping; larger capacity Johnson Pump models are available for heavier duty needs.

What voltage does this bilge pump run on? The Johnson Pump JP-21405 operates on a 12 volt DC system.