'01 sanger v210 - fuel gauge accuracy?

My sanger v210's fuel gauge seems to stay pegged around "F" on the fuel gauge for the longest time. Next thing I know I look at it and I'm damn near "E". I filled up from there and put about 25 gallons in the tank. I estimate the next run out I burned through maybe 8-10 gallons but the gauge still reads around full.

Also, the gauge doesn't read anything at all until I start the motor. i.e. I turn the key to the ON position and I get readings for volts, temp, etc. but the fuel gauge does nothing. Start the boat and the gauge comes to life.

Are either of these things normal? I think I have a pretty good feel for what I burn in gas per day and since I gas up every time I go out it's not that big of a deal but I figure it would be nice to have someone look at it if I thought it was malfunctioning.