Fuel Flow meter

[Roy Smith]

Hi all
have just had a Yamaha fuel flow meter fitted
How ever the instruction or rather the lack of them as left me puzzled
also when on the move it will jump between 11 gals an hours to 13.5.
we have checked on the connections etc.
dose any body have the same problem or able to give me a few tips on what to do please.

[Pete7]

Roy, seem to remember the instructions on the Navman one says the flow meter has to be installed in a vertical orientation to stop bubbles giving a false reading, eg the fuel flows upwards. Might be worth a try.

Pete

[Mark Halliday]

Roy

Also Navman related. I spent a bit of time calibrating mine. Took a while to get set up.
Also I seem to remember reading that some engines get fuel in gulps, i.e. not a constant flow. The Navman units have an averaging setting to smooth out the peaks.
Agree with Pete. sender should be mounted vertically. Also make sure that it is firmly fixed to the hull. If it can move around it will give false readings. Clips on the hose are not good enough.

[Roy Smith]

Got a replay back from Yamaha man , the reason the meter fluxulates is that the fuel injection recyles the fuel it did not use so by passing the fuel flow meter
showing a lower rate of fuel use.
(dosent sound quite right to me) but that what they said.

[Daniel]

This is true, as so far as i know you can't use a fuel flow meter with this kind of engine/fuel setup. Sorry!

[jim68585]

Originally Posted by Mark Halliday

Also Navman related. I spent a bit of time calibrating mine. Took a while to get set up.

Mark

How many times did you need to run the calibration to get an acceptable accuracy? Mine remains almost 20% pessimistic after a couple of goes (safer than optimistic I guess!)

Jim

[Erin]

Originally Posted by Roy Smith

fuel injection recyles the fuel it did not use so by passing the fuel flow meter showing a lower rate of fuel use.

That's about right in that most fuel injected engines have a small amount of feedback, although this is normally inside the engine into a small reservoir and not back into the fuel tank. Unlike diesel which does return fuel to the tank, and for which you need two fuel flow meters so that the difference can be measured and therefore show 'actual' fuel consumed.

Also make sure it is not too close to a bend in the pipe where air locks could occur.

I spent some time calibratin my Navman but I'm still not happy so will be doring some trialing this season.

Keith

[Rogue Wave]

they are buggers to calibrate we have got the diesel system and we are just aboy there but it's taken lot of effort!

[jim68585]

what did you actually do to get it more accurate? As a non-tehnical person, grateful for any easy to follow guidance!

[codprawn]

I believe with some of these systems you can alter the actual sampling rate to compensate for optimax type systems - the longer the sampling period the more accurate the results.

Has anyone found this to work???

[Erin]

To calibrate you just set the meter to zero or take a reading of fuel used so far and then fill up you fuel tank to the brim. Then all you need to do is have a play in your boat until you've used as much fuel as possible and then refill the tank to the brim. The fuel meter should be telling you you've used as much fuel as the petrol pump says. If not you press the + or - buttons to adjust the meter to match. Easy really. The more fuel you use in the process the more accurate as it evens out any inaccuracies.

[jim68585]

if only it was that easy - we've done that a couple of times and the meter is still way out!!