I inherited one with my boat and still have not figured it out. I was also warned by a mechanic that those fuel sensor wheels have been known to jam and impact fuel flow. I'm tempted to just pull the thing out of my boat
I cut a slot in the stern board that covers my tank and marked off 5 gallon increments: very reassuring to turn around and get a visual rather then relying on a sensor that May or may not be accurate
I keep a log---distance travelled, fuel burned, when I do my long summer trips-- I guess That's considered Old School but it gives me peace of mind
Even though my kicker is plumbed in to the main tank I installed a quick disconnect on the fuel line entering the Racor--- on a two week trip I'll typically run the kicker off a 6 gallon separate tank-- much easier to track real fuel consumption on the main engine when the kicker is not part of the mix
Wish I could figure out the Lowrance sensor, though---it would be nice to have the electronics to fine tune proper RPM's and gas burn for long distance cruising
I also stash jerry cans of fuel on islands as back-up--wow, I am Old School!