It will run about 1:30 on a full tank of fuel, perhaps 1:25. I knew this would be a problem, but decided it wasn't that much of a problem. In reality, now that my machine has been through a few hundred hours, the fuel tank isn't as much of a problem as anticipated. I have a 2 1/2 gal can within easy reach on the trailer, good nozzle. I've just become accustomed to refueling at proper intervals -- it has been a long time since I've ran it out. Mine typically runs through four tanks per day, sometimes five, and at the most six. But, by now, I know my route, how long each job takes, and if I can make one or two properties.
My point: Small tank is not as much of a problem in reality as anticipated.
Have you been able to use the HRX217 to mulch/bag leaves yet? I'm very interested in seeing how the unit does with leaves/fall-cleanup.
Here's a video from Youtube that shows some capabilities of this machine: