Oil out of the exhaust is normal for all 2 strokes, new or old.
it just may seem like there's a lot of oil because you are running a much richer oil-fuel ratio for break in.
Mileage?? does anyone even really care about mileage?
I know i don't.
what scrfew are you referring to?
what kind of carb do you have?
if you have an nt carb and you are turning the screw in, you are increasing your idle, which explains why it's racing all the time.
if you have a cns carb, then you will have an air-fuel ratio adjustment screw. you turn that screw in (clockwise) for a leaner air-fuel mixture, and screw it out (counter-clock wise) for a richer air-fuel mixture.
you fuel-oil ratio is different than your air-fuel ratio and sometimes too much oil is referred to as being to rich.
true, too much oil is a "rich" mixture, but you need to be clear if you're talking air-fuel or fuel-oil ratios.
telling someone that their engine is running too rich when referring to the fuel-oil ratio could mislead then to think that you're talking air-fuel ratio.
if they start adjusting the air-fuel ratio instead of looking at the fuel-oil ratio, they could make the engine run too lean, and open up a whole different can of worms.
get it running well enough to get it broken in first, drop to a 32:1 fuel-oil ratio.
then you can adjust your air-fuel ratio (if you have a cns carb) or you may have to re-jet the nt carb.
If you have an air leak at the carb to intake manifold, you will be creating a lean condition which will make the engine race like crazy as well.
any time an engine is running lean the idle will go up. any time an engine is running too rich, the idle will go down (of corse, i'm talking air-fuel ratio).