Saturday, January 10, 2015

Installing it on the boat!

I managed to install it on the boat today! I haven't finished with hiding the cables because I have to do some other things as well.

What I managed to do is take some pictures of where the flow meter is installed. I removed the Both switch.

The negative (brown) cable is connected to ground.  In this setup I am connecting it to the negative of one battery. 

Firstly I connected the positive wire (blue cable) to the COM port of the BOTH Switch (1,2,Both Battery switch) so that it always runs when there is current flowing to the engine.

The sensor must be installed according to the flow that is usually writen on the sensor. Most sensors support only one direction.

Take notice of the angles the flow sensor supports and install accordingly. 

Here is another pictures of where the device is. I will eventually mount it somewhere else, you can find the correct place for your setup.

When I will have some spare time again, I will show you the tidying up I am hopefully going to do.


  1. I've been reading your posts for a couple days now, thank you so much for putting the time and effort into documenting your trials and posting your findings.

    I agree that one of the most difficult parts of this project is deciding on a meter. I have a 7.4L merc with a 4bbl carb that consumes 30+ GPH (113 lph) at wide open throttle and I really don't want the meter cutting my fuel flow. I searched long and hard for the blue version of the microstream you used; but even if I could find one, it would be at the lower flow rate, and $350 for a new one kinda kills the whole project.

    I finally settled on two FS-3400AH's from I'm just going to split the fuel line and rejoin it after the sensors. You're code for two sensors should work perfect in this case. Also, if one of them jams up (dirt, etc.) I'll have a second path as a backup. My only concern with these sensors is that they have two calibration ranges, at 12lph, the pulse/l goes from 1724 to 1818. It's not much of a change though and for my build, 12lph (24lph for two sensors) comes in at 2000 rpm. I'm really only concerned about my fuel economy between 2500 and 4000 rpm.

    Finally, I'm going to adjust your sketch for gallons instead of liters, I'm still in the backwards part of the world that doesn't believe in the base 10 system. If I get ambitious, maybe I'll figure out how to recompile the APKs, but for now, I'm just going to pretend that L stands for Liquid Gallons.

    I'll let you know how it works out; it's going to take a couple weeks to get all the parts in, can't wait. Thanks again!

    1. I got 6 spare OF05ZAT Sensors. If you get Stuck with fuel flow just give me a shout :)


    2. Hi,
      I would be really interested in buying 3 of the spares you have, are they still available ?
      Thank you!

    3. Hello,

      sure but you can also buy from here. Price is really good! Still 4 left!

  2. Great work! Could I order a complete setup from you? Unfortunately I don't have the time to assemble these things together myself (and I don't think I have the knowledge either). /Jacob

  3. First I ordered the fake red flow sensor. Testing had shown that with 10l/h flow, it had 165 pulses per liter and with 20l/h flow 211 pulses per liter. So with fake sensor, the pulse count depends very much on flow rate and sensor is completely useless. Now I'm waiting for 2 used original sensors to arrive. I hope that original ones doesn't depend on flow rate so much. My Vator 17 HT takes approximately 20l/h on cruising speed of 22 knots with Yamaha 150HP 2-stroke-

  4. Hi! If i want to change to code to Arduino and print to LCD instead of bluetooth and print liter per hour instead - can you help. I´ve written the code for LCD but need to change to liters per hour instead of seconds.

    1. You just have to replace:

      literspersecond = (PulseSensor/pulses);

      with this:

      literspersecond = (PulseSensor/pulses)*3600;

      on the Arduino code at the end!

  5. MaleBuffy

    I realise that this is a long shot as this blog hasn't been updated in while, I am interested in a flow meter for my Mercury 75 HP 2 stoke outboard, do you still have any OF05ZAT and if so are you willing to sell one?

    1. I am still here :)

      I still have some. Where do you live?

    2. Malebuffy Great I live in Scotland where are you?

    3. I live in Switzerland now. I can send you one. Just need the shippings costs.