Can these just give up?..with a feeling like the engines been cut off

Cars been run down to FITP all ok, however on the way home the engine stalled slightly but came back.(didn't help not dropping to second mind). got it home and it failed to start after being turned off.. checked fuel all ok and added another jerry can even pour some down the carb to make sure n still nowt.

so switched to electrics and found ive no spark. Ive got 12v at coil but when cranked the sparks are blank, should there be 12v reading at the pin end of the amplifier lead? or does that take source direct from coil once connected to amplifier?. Also how do you get a bottom fitted amplifier off??

old girls done me proud today until now so wanna get her going again