Small Engines (Lawn Mowers, etc.): Homelite line trimmers

Question
I have problems with what seems to be the carbie in my Homelite liner trimmer Model FR 2020 UTS20788.
Notice only one adjustment screw , with blank pole adjacent, is this also a fixed adjustment screw.
Unit completely overhauled, new carbie kit, good spark etc.
Will start when needle screwed right out but wont run on or accelerate. Local mechanic suggested soaking metal carble (seals removed)in acetone to remove lacquer build up, done so but still won/t start.
Thinking of buying replacement carble but considering cost might be throwing good money after bad.
Unit hardly used no carbon build up and has good compression
any suggestions

Answer
Did you check to see if the o-ring on the back of the engine crankcase is sealing?  I have found these to leak.  A quick fix is to remove the back engine cover to access the o-ring, clean all the grease and oil from the housing and engine then seal with Permatex #2 non-hardening sealant.

Yes, the second blank pole is a fixed jet...very bad design but EPA forcing stricter emission controls so equipment manufacturers have to comply.

Eric