Went 10 mins no problem lastnight with jp-3, I did lean it about 1 1/2 hr on the top and drove with a lite finger with the fuel left in tank I think it would have got to at least 12mins. I could not be happier with these engines, the two I have are showing no signs of giving up and each have approx. 4 gallons and one had an air filter pop off for about 5 mins. at one race. Both are bone stock.