I'm having exactly the same issue as the two questions above. I'm not sure what you mean by 'clip spring' and 'switch shaft'. Is the clip spring in the new knob? There seems to be a plastic nub inside the new knob that is blocking it from going on all the way.
Ken for Model Number Jenn-Air CVE4270B-C
Answer Hi Ken, Often when we here of an issue like this, it is due to a piece of the old knob that is still on the shaft of the switch. Many times the old knob is broken and a clip or spring is stuck on the shaft of the switch and when you try to put the new knob on it will not fit. Take a good look at your old knob and the switch shaft and compare to the new knob. If this is not the case, get back with us and we can examine further. Hope this helps!
Wrong knob, will NOT properly mount on Jenn-Air stove tops. Part is clearly marked KIP 5925, need KIP 5915! First photo shows correct knob, second shows wrong knob.
Robert S. for Model Number CVE4270
Answer Robert, according to the manufacturer the knob 71002187 is the correct replacement and will fit your product. This is the only knob offered for your unit that is black in color. Thanks.