RE: engine dies when ignitor disconects
Start the engine at full throttle and set the high speed needle for a rich scream. This setting should be a noticable drop off from peak rpm. Don't be afraid to look for peak rpm, just do not lolly gag there.....open the needle up as soon as you find peak rpm to a lower note. This is a base line starting point, follow the OS manual for the rest. If the engine is forced to run with too rich of a setting, then it will die after the ignitor is removed.
If the plug is contaminated...or used up, it will light but will not support the catalytic action....so a new plug might in order, too.