The 264 transducer on my Floscan is not working correctly. I can buy a replacement from Floscan for around $300. Are there any other fuel flow systems available for $300 or less. I do have an older Raymarine C70 MFD but I don't think this has an option for fuel flow input.
I wish I could give you my real world experience but I have never actually set up my NMEA 2000 system for operation on my boat (yet). I know you said <$300 but if you decide to do a general electronics upgrade, then you might want to look into getting a chartplotter with NMEA 2000 network compatibility. This will allow you to plug MANY different devices into a network backbone and you can monitor them from your chartplotter/fishfinder. Pretty cool stuff. You can then purchase a $200 fuel flow sensor such as this
Lowrance Fuel Flow Sensor (NAVICO and Suzuki are the same I believe) and it would be plug and play with your chartplotter, even if your chartplotter is a completely different brand.
Or if you didn't want to go all in w. NMEA 2000 you could instead just buy the
Lowrance LMF-200 and it will be a single dedicated fuel flow gauge.
Also, this thread might do better in the Electronics forum.
