tha actual ignition is by chemical process the heat just helps it along.
there are two strokes with rings& have been for years.nothing wrong with ringed engines. they are more tolerant of dirt than ABC setups and break in quickly. the ABC setup has the tapered cylinder liner .this allows more power to be developed along with schnnerle porting which most modern engines have. the Aluminum piston running in a Brass sleeve Crome plated.your carburator in the FP/La engines is really a simple airvalve as opposed to true carburation adjustment with high and low speed adjustments .the air bleed works but not always that effective . it does work however.with bushed engines such as yours opposed to ball bearing engines its more important to insure lubrication to the front bushings via some additonal castor in the fuel or at least as was mentioned ,slightly rich setting.lack of ball bearings makes it much less expensive to manufactuer& maintain.the small size of the carb is what holds back the FP/LA series more than anything. it also makes it have good fuel draw & reliable idle.
one other thing should be mentioned.unless you live in an ususual place where weather/temp changes drasticly through out the day , needle valve adjustments should not be neccesary once set.minor ones perhaps but constant fiddle & tuning indicates other problems & often indicates lack of knowlege of the real trouble.