Location fuel sensor

[ireilly]

Have a 2012 R-27 Ranger Tug. Need to determine if the fuel sensor is accessible to see if it is operating correctly.
Filled up the tank yesterday and took a 9 hour trip with the flow rate of approximately 5.9 gal/ hr. Fuel gage showed 100% on the Garmin and full on the Yanmar analog for most of the trip. At approximately the 8th hour the Garmin suddenly started going down to 88% and the analog moved off of full. By my calculations I had used approximately 48 gallons which is close to a half tank.
The only common denometer seems to be the fuel sensor. Is it accessible? If not, are there any other solutions besides the flow rate time hours to determine usage and subtraction from the tank total?

 

[baz]

As far as I know, The Garmin chartplotter's computer determines fuel left based on the fuel burn. If when you topped up the tank and entered the amount of fuel into the Garmin's computer via the menu option, then the fuel burn should then be used to calculate the fuel remaining.

Thus (assuming 75 gal full tank) if you ran for 9 hrs at an average of 5.9 gal/hr this should result in the Garmin displaying

75 - (9 x 5.9) = 75 - 53.1 = 21.9 gal remaining or some 30% remaining.

On my R-25 (Classic) with a 75 gal fuel tank I don't believe it had a fuel level sensor and relied on the Chartplotter and Yanmar display. I never had an issue not believing the fuel level readouts.

It's important to enter the amount of fuel in the tank accurately on the ChartPlotter when you caste off.

 

[ireilly]

When I topped off the 100 gal tank, I initialized the Garmin. It immediately went from the previous setting to 100%. Previous posts indicate that the fuel sensor is unavailable without making an access plate in earlier boats. I was hoping that the factory would have corrected this deficiency but so far it doesn't look good.
Many posts indicate that they don't rely on either gage and do as you suggested. As a backup I agree but somehow believe that there has to be a simpler solution than making a new access hole to get to the fuel sensor.

 

[tlkenyon]

My Garmin fuel readout is quite accurate. I have topped off from 5-gal cans, very slowly, and it takes almost exactly the amount that it should to completely fill the tank. On the other hand, the Volvo engine display fuel readout is absolutely worthless. It stays at 80 until there is actually about 60 remaining and then it starts dropping, but is always 20-30 gallons off. I have tried the calibration exercises, to no avail. Oh, well.....

Smooth seas and full tanks....

TK