oh and a bit of advice, 90% of local hobby shops sell blue thunder race fuel, i strongly advise against it. most shop owners will tell you that its pretty good stuff, and it is. but once you run with a great blend like ODonnel 20% or Byron, you will never be the same.
using good fuels may cost a tad more, but engines running good fuel are typically easier to tune, to keep in tune, and to keep clean. my LHS ran out of odonnel so ive been using a bottle of blue thunder race 20 i had laying around, and after 2 tanks i had to clean the gunk out of the muffler and header! i couldnt believe how dirty it was. i cant for the life of me imagine how i used the stuff for so long. so save yourself a headache and use a good fuel. most high end fuels use synthetic oil blends, and less of it. the high tech oil blends protect your engine in concentrations as little as 8%. most cheaper fuels use much higher concentrations of more traditional oils in concentrations as high as 18%. the extra oil runs hotter and dirties the engines fast. they foul glow plugs too. so fuel definitely isnt a place to skimp