Two problems here (one of them mine 
). The resistor values are a bit wrong, it looks like the 555 draws current on the trigger lead so R3 should be 560K and R4 should be 680K. For me that makes pin 2 6.3 V and grounding pin 2 then reliably triggers the 555 (I dug one up and tried it!) Initially I saw the same problem as you: the 555 would trigger once and then hang. It turned out my C3 (a tantalum cap) was defective. With pin 6/7 disconnected the capacitor was only getting up to about 4V (likely due to leakage in the cap) which isn’t enough to trip the high side comparitor reliably. When I replaced the cap with one that gets close to 12V with pn6/7 disconnected the circuit started working. It would be worth disconnecting pins 6/7 and making sure the R2/C3 junction gets close to 12 V as it should. From the voltages you quote (.2V at pin 2 which is low and thus continuously triggered and 11V at R3) your problem is the coil is disconnected between R3 and R4. There needs to be a DC path (either the coil or a jumper across where the coil should be) so the voltage divider functions. The coil (if it isn’t seeing any sparks) will be basically 0 ohms and not affect the voltage divider. When a spark happens the voltage induced in the coil is supposed to drive pin 2 lower than 3.6 volts and trigger the 555. Hopefully the 560K/680K resistors are large enough that the coil will produce enough voltage to cause the trigger. As noted above you should be seeing about 6.3V on pin 2 of the 555 with it not triggered. If I reduce R4 to 390K (which produces 4.3 v on pin2) the circuit triggers once and then hangs, so it looks like there is some slop in the supposed 3.6V trigger threshold. Hope some part of this helps! Who knew 555 circuits were this complex , they usually just work. Once this circuit works with grounding pin 2 reliably then the excitement will be if the present coil provides enough voltage to reliably trigger the 555. If not you may need to increase the number of turns on the coil to get more voltage.
Peter