Maretron M2AR Fuel Flow Sensor – 25–500 LPH / 6.6–132 GPH

The Maretron M2AR Fuel Flow Sensor is a marine-grade, positive-displacement flow sensor engineered to measure inline fuel consumption in medium to large marine diesel and gasoline engine applications. When used with the Maretron FFM100 Fuel Flow Monitor, this sensor delivers reliable real-time fuel flow data — helping you monitor consumption, optimize engine operation, and improve overall fuel efficiency aboard your vessel. 

Built with corrosion-resistant materials and a rugged internal rotor design, the M2AR accurately captures fuel flow between 25 and 500 liters per hour (equivalent to 6.6 – 132 gallons per hour) — making it well-suited for boats with mid-range power systems. Its compact housing and ¼″ NPT female port allow easy installation into existing fuel lines (an adapter may be needed depending on your plumbing), while the 1 m (3.28 ft) cable simplifies connection to the FFM100 module. 

This sensor’s accuracy (±0.25 % with proper calibration in the FFM100) ensures trustworthy data for diagnostics, logging, and display on compatible NMEA 2000® systems — providing captains and crew with actionable fuel consumption insights. 

Benefits

• Enables precise fuel usage monitoring for better trip planning and cost control

• Works with the FFM100 to report fuel flow to chartplotters and multifunction displays

• Helps identify abnormal fuel consumption and potential issues early

• Promotes efficient engine tuning and load management

Applications

• Monitoring fuel supply line flow on single or twin engine boats

• Integrated fuel consumption reporting for cruising or commercial vessels

• Diagnostic data for engine tuning and efficiency evaluation

• Paired with FFM100 for NMEA 2000®-enabled fuel flow data display

Final Recommendation

The M2AR is the correct choice for engines where the maximum fuel flow (including return) falls between 6.6 and 132 GPH. If you have a smaller engine (under 200HP), you might consider the M1AR, which is better suited for lower flow rates (up to 26.4 GPH).