Although I haven't tested the project on my boat yet (damn you Chinese waterproof case), I am going to tell you a little bit why I decided to test my project with the FS-3400AH aka FLOWFUEL30L0.
Thing is, I started with the FCH-M-POM-LC 6 MM fom BIO-TECH. This was used in another flowscan project, however for a smaller outboard (40 HP). The "problem" is that although the flow rates it can handle are suitable for engines like my Tohatsu M140A2, I am afraid that the 3mm nozzle is just too small. This has been confirmed with the person that used this flow sensor on the 40HP outboard.
Since I was still coding for the Arduino and Android, I was searching for a better suitable flow sensor. I contacted BIO-Tech and they suggested I should use the FCH-midi-POM which has a 6mm nozzle. That would fit OK, but at the Price of about EUR 42, it wass too expensive for what I had in mind. I ordered one just in case, however.
So back to the drawing board, I managed to find another sensor that probably fits my needs. At first, the downside was the it supports flow rates from 1L/Hour to 60L/Hour. My engine burns 54L/Hour at WOT. I ordered it since I thought that I wanted to measure fuel flow at cruising speed and not WOT. The good part however is that, buy blowing into the sensor I managed to get readings for over 60L/Hour. Air is different from liquid for sure, but since this is the only 6mm nozzle sensor I have received, I will do the tests with this one. So my priorities are:
2. FCH-midi-POM3. FCH-M-POM-LC 6 MM (probably not going to test it at all)