My gas guage only meters about 16-18 gallons on the guage and then if i fill it passed the full mark it sits up there forever, i have a 26gal tank IIRC and idk why its off so far, and my pump is F-ed up i have to double or triple key it sometimes cold to build pressure i know cause i have a bad residual check valve in it, leaking back into the tank. just wanted to rant.,