KAB4 Boil times?

How fast are you guys getting your water to boil using the Bayou KAB4?

Tonight I tried to boil about 8 gallons of water in a converted keggle and gave up after an hour. One reviewer on Amazon says he got 10 gallons from 40ºF to boil in about 20 minutes!!

I have my flame adjusted so there is just a hint of yellow in it. I was going to use this to brew tomorrow but I think my old 6500 btu burner from a fry kit boils faster than this guy does.

I had one and used it 4 times before selling it because I went electric. Three of the times I was from whatever my run off temp was to boiling in about 15 minutes max (7 gallons). The other took a little while longer, but nowhere an hour.