I get 12 minutes on 16 ounces from my 150 (Ultimate bipe at just under 10 pounds), with perhaps an ounce left in the tank. However, my main needle is 2 3/4 turns out. I think the engine is still on the rich side, but it sags sometimes on take-off when I lean it a bit.

This engine is new, with just over two gallons through it, so perhaps it is still breaking in.

Yes, the sound is great, but LOUD. I have the factory flexible exhaust extension installed; a muffler, it ain't...