If there is too much Acetone in the tank or if the tank has not been
kept upright; the Acetone can come out and cause spits,yellow and
other flame problems. Always use with the cylinder upright and
avoid transporting or storing in any other position. Other times the
problem can be a dirty orifice etc. Use care in cleaning as a tip
can be ruined if the orifice is damaged or enlarged. Lastly, never,
ever adjust the regulator to deliver above 15 psi; Acetylene becomes
unstable and dangerous at approx that pressure.
Dan Wellman