Fuel Flow Monitor

Maretron FFM100-01 Fuel Flow Monitor

A precision NMEA 2000 fuel flow monitor that calculates real-time fuel consumption, distance to empty, time to empty, and fuel economy — with accuracy approaching commercial vessel systems costing far more.

Why It's Worth It
Most boat fuel gauges tell you how much is in the tank. The FFM100 tells you how fast you're burning it, how far you can go on what's left, and how many gallons per hour your engine is currently consuming at any throttle setting — data that translates directly into fuel savings on every passage. The accuracy comes from three things most cheaper systems skip: positive displacement metering (counts every drop physically, not estimated), true temperature compensation (fuel returning from a diesel engine runs hotter than supply fuel — without correction that alone causes up to 5% error), and reverse flow detection (injection pump pressure fluctuations cause momentary reverse fuel flow that less accurate systems incorrectly count as consumed fuel).

For diesel engines with a fuel return line, two sensors are required per engine — one in the supply line, one in the return — and the FFM100 calculates net consumption by subtracting return flow from supply flow. For gasoline engines with no return line, one sensor per engine is sufficient.

Use
Connects to NMEA 2000 via standard Micro-C. Flow sensors connect via screw terminals on the module. Mount in any orientation — horizontal, vertical, or upside down — in a dry or damp location away from engines and engine rooms where temperature exceeds 130°F (55°C). Configuration requires a Maretron DSM250, DSM410, USB100, or IPG100 — program the K factor printed on each sensor into the FFM100 for maximum accuracy. Flow sensors (M1AR, M2AR, M4AR, M8AR, M16AR) are sold separately — select the sensor with the smallest flow range sufficient for your engine's consumption rate.