Last 2 fountains I've had, fuel gauge isn't accurate at all. Shows full all the time and the when you see it fluctuating it's empty!

I have 2 small extra tanks. Always have them for reserves.

They have adjustment screws on top of the sending units. I got mine to at least read somewhat accurate from full to half, after that it's a crap shoot

I get about 1mpg,, cruising with twin 800's in old 38 Fountain with SSM drives. But they arent tuned for alcohol like some boats i've seen where the transom looks like the bottom side of a weber bbq lid after a run.

I was thinking you were going to say...drinking beer I get about 1mph, but when you hit the "hard stuff" (alcohol) the throttles go forward and you get 2gpm.

Thanks a lot. I didn't know that. I'll check it out.

All I do now is open my other tanks when I see my gauge fluctuating.