hey there kharoff , glad too see you are stiill baving at the mouth for your rc!
soo much that it keeps you out in the cold till midnight ... yeh haa ! now that's addiction!
what your experiencing is normal unfortunaly for nitro when it's cold and when they are in the break in period. i don't know why but alot of guys getting thier first rc always pick when they WILL have trouble. ( my first was in janruary, try and start a nitro at minus 20 and not get frustrated . lol )
for the first half a gallon you may need tio keep adjusting the screws a little as the motor uses to fit.
then it will stop needing ajustment as often .... now here is the thing though!!!
each day and from one hour to the next a nitro engine may seem to run differnently.
you could spend all day every day tuning your car to perfection and all that will do is make you go nuts!
the best way to deal with this is to ajust more rich, and just learn to live with the way it runs, because by the end of the tank you will see that it usually much differnet! the engine warms up and the hole chassis also gets warm and changes how the engine performs.
so if you want your truck to be super peppy and spin easy when it's cold, your motor will be sooo hot but the end of the tank , you will need a new motor before the end of summer !!!
it should be hard to keep running when it's cold, and then buy 1/4 of the first tank you should get normal idle and not stall on brakes.
as for the needles, i don't play with my needles at all once i've finished break in. for about 6 gallons of nitro, then the motor gets worn and needs adjusting.
also now you ask the right question about how th ajust the needles!
it's never set buy number of turns, always buy temperature and performance.
idle- is high or low like giving it gas or trim.
set this so when on brake motor does not stall and wheels do not spin on block.
high speed- at high throotle you want steady smooth accleration all the way up rpm band and temps should never keep going up.
to rich- lots of smoke, gurguling and sputturring instead of acceleration, low top speed.
to lean, crazy accleation then bogging , high temps, engine seems to sputer at higher rpms, glow plugs burned out .
low speed needle is important and can affect the high so recheck temps at high speed as well.
to rich, low idle speed , stalling before clutch disengages, sluggish acceleration, stall after 1 second idle, after letting go of gas idle is high then slows down
to lean, higher and higher idle speed the more it warms up, too much acceleration of idle then stumbles.
thes are just some symptoms and the more you use your truck the better you will know it's little secrets.
hope this helps, but there is no magic solution, these things have character in many ways, that is what makes them better and worse than electric at the same time.