With this step be patient, you need too heat the black tubing right at the poppet to just the right temp. the safest way to do it is to dip the last inch or two in a pot of boiling water for about a minute.
As soon as you pull the poppet out of the water start to work it out of the tubing with two pairs of pliers.
Be very careful not to scratch the poppet or break the hose. Don't squeeze to hard on the poppet or you will crush it an then you might as well buy the MFI kit cuz the cost about $80.00 a piece.
You will only have a few second at a time to work the poppet out before it needs to go back in the pot. Be gentle and it will come out.
If you are using a heat gun it only takes a few seconds to work it out, but if you over heat the tubing it will become brittle and increase the chance of making your problem much worse.