K so I'm thinking bout going to a twin set up. I found on here a 98 with twin 500 HP 502's running easy what kinda gph do u think I would put down?

20-25 gph cruising and not running too hard. If you have more idling time in and out of harbors that number could go down to 15-20 gph. But just straight cruising at 2800-3000 rpm figure close to 25 gph. That is what my 35 with twin 500EFI's did.

Asking fuel economy on a twin engine performance boat is like going on a honda civic forum asking towing questions. It will be horrible on gas. But like anything you have to pay to play.

That response didn't take long. Yes, of course it is horrible. But there are different ranges of horrible. I can understand wanting to know what to expect in the wastelands of horrible mileage!

It's nice to know, because the fuel gauges on fountains are pretty much useless!!!

How true! I will use half a tank of fuel before my gauge moves.

It is pretty common on a V bottom boat because of the shape of the hull the top 1/2 tank holds much more fuel than the bottom half. So once you get below a 1/2 tank the fuel gauge goes down really fast because the bottom half is really only 1/4 of the fuel.
On my boats when I get to 1/4 I am looking for a place to get more gas.

Yes, when it reads 1/4 your actually out of gas!
I found this out the hard way late last season, my gauge showed 1/4 as I was heading to get gas and after only a mile or 2 it ran out 20ft. from the gas dock.

JD I ran out of gas in my 32 early last season with 19 hours on my engines leaned it out 14,000 later I will never run out again. I just put the new tube type fule unit in my tank to correct the problem just as bad if not worse.
Rich