bought a 74 911 last summer. it has an 81 sc motor in it. car ran well but had two minor problems:
surging idle when cold , and backfire when starting a cold engine. after storing car for the winter
I ran it once ( ran ok) but now it will not start. car turns over but will not fire. I static timed it and that
seemed within reason. pulled plug wire out of cap , turned over and had visible spark jump so I don't
think its an ignition problem. does anyone have any suggestions on trouble-shooting the cis fuel system?
Thanks

 

I have a feeling your CO mixture is way off, which is why you were having the backfiring. I would richen it up a bit and see if it starts.