With air-acetylene, carbon buildup is a problem. Acetylene is
inherently carbon-generating. I believe the smaller torch tips have no
filters, but take a look.
Unscrew the tip from the torch body, and take a gander at the
non-business end. If you see lots of carbon here, time for an extended
acetone bath. Acetone is what holds dissolved (read the label!)
acetylene in the non-hollow cylinder. Bath completed, and with ample
drying time, try firing up the tip. See if the flame quality
improves.
If not, take another gander. There should be a grainy-looking thing
in the non-business end. That’s the filter. Depending on the make of
the tip, it may be allenwrench extractable, or a cheaper tension ring
may hold it in place. Whatever the configuration, see if you can
replace the filter only. Should save money, if not time.
Then again, maybe a new tip is in order.
FWIW from the well-read redneck,
Dan Woodard, Indian Jewelers Supply Co.