Fuel Flow Sensor (0.53 To 26.4 GPH)

Maretron M1AR Fuel Flow Sensor — 0.4 to 6.6 GPH (M1AR)

A precision oval-gear fuel flow sensor that puts real-time fuel consumption data on your NMEA 2000 network — sized for smaller diesel engines in the 0.4 to 6.6 GPH flow range.

Why It's Worth It
Positive displacement oval-gear metering measures every drop that passes through the sensor by physically counting rotor revolutions — not estimating from pressure, not averaging from an impeller — which is why the M1AR achieves ±0.25% accuracy. That's nearly the accuracy of commercial vessel fuel systems costing far more. Temperature compensation is handled by the FFM100 module, which corrects for the fact that fuel returning from a diesel engine runs hotter than supply fuel — without correction, that temperature difference alone can cause up to 5% error in consumption calculations. The FFM100 also correctly accounts for momentary reverse flow from injection pump pressure fluctuations, which less accurate systems count as consumed fuel.

Important Installation Note
Diesel engines with a fuel return line require two M1AR sensors per engine — one in the supply line, one in the return line — plus one FFM100 Fuel Flow Monitor. The FFM100 calculates net consumption by subtracting return flow from supply flow. The sensor must be mounted with its rotor shafts in a horizontal plane (parallel to the water surface) — incorrect orientation causes measurement errors. Install after the fuel filter, with a 200-mesh strainer if not already present. Never blow compressed air through the sensor — it can over-rev and destroy the rotors. Always prime the system slowly with fuel before starting the engine for the first time after installation. Use liquid thread sealant, not Teflon tape, on all pipe threads.

In The Box:

M1AR Fuel Flow Sensor
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Qualifies for Ground and 2 Day

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* ALL WARRANTY IS THROUGH MANUFACTURE *