Fuel guage and capacity

[FishOff]

We recently became owners of a 2020 R31s. Specs say it has 180 gal fuel capacity.
When fueling for the first time the guage said full (180g) well before the tank was full. I was able to put in another 20 or 30 gallons (sorry, not as accurate as I'd like but these are the learning curves - next fuel up I'll get a more accurate number).

Anyhow, my question. Is this normal? Do these tanks have additional capacity or are they truly 180 gal. And if they are then I should probably recalibrate the guage?

 

[ShaneM]

There are some threads on how to recalibrate your fuel gauge, but accuracy tends to be an issue because our boats are almost never level. If you're bow up due to acceleration or stern-heavy due to gear, the gauge will read high.

Seems to be a consensus on the boards that the Garmin is more reliable. Top up your tank, update the Garmin to reflect that it's full, then update whenever you add fuel to the tank.