The flame is very yellow though still with a blue cone when using
the new full tank.
Sounds like you’ve got what’s called a “spitter”. This means acetone
is getting or has gotten into the valve and is being sprayed out with
the acetylene gas. Two possible causes. One the tank was not upright
when it was transported. In this case this is a temporary situation.
The other is that there is too much acetone in the tank. In this case
I would return it to the supplier for another tank of acetylene. I
few years ago I had to change suppliers because all the acetylene
tanks I got from them were spitters.
Although you can still use a tank that is a spitter I can imagine
that the acetone is not good for the diaphragm in your regulator.
Silversmith and Lapidary Artisan