Usable fuel and Garmin / Yamaha gauges

[Joby]

Hello,
The spec for my 2024 Solara shows a 116 gal fuel tank. We have physically verified this by inspecting the factory stamp on the tank.

Both the Garmin and the Yamaha CL5 are in 'synch' - showing the same amount 'remaining' in terms of percentage. And they both show a 116 gal tank installed.

Refuel stop number 1: gauges show 35% remaining, yet she takes 96 gallons to fill. Refuel stop 2 : gauges show 47% remaining, but she takes 79 gallons.

(Stating the obvious)This error is working against us; showing much more fuel than what's actually there. By the math above, these gauges think it's more like a 135 gallon tank. I am having to subtract way more than the 'Industry standard' 10% for 'unusable' fuel capacity.

Someone with knowledge on how to reset or calibrate the Garmin without starting from an empty tank..?

thanks in advance,
-Joby

 

[Mike and Sarah]

I believe there are are two fuel levels available.
First is a float gauge like your car. This one reads percent This one will bounce around as the boat moves and rocks. That one needs to be calibrated with a full tank.
2nd is gallons used on the Garmin. We reset there by going to options menu on the fuel gauge page. We reset every time we fill the tank. I believe it says fill all tanks. (We have 2 tanks) If you use gallons used and or remaining you will have a very accurate reading of fuel left in the tank. We are always within a couple gallons when refueling.

 

[Rocky Lou]

I spent quite a bit of time on this question when my boat was new. The Gamin digital GPS method tends to be more reliable since it doesn't get affected by boat movements and resetting is just a push of a button. However, the Yamaha traditional analog measurement has a far more complex calibration process. I decided that, for an offshore boat, I should simply regard 1/4 tank as completely empty and not worry about reconciling both gauges. Unlike my cars, that other's drive, no one is taking out my boat without me, so it's not hard to enforce.