pretty simple shop they have there, the tools are basic bicycle workshop toolset and the SST tools are what any other shop would have regularly. infact I think I used to hack up most parts like that to make life easier.
anyway
the engine needs to be tested properly for correct operational parameters.
1 engine health
2 engine induction
3 ignition system
According to you - you say the engine is completely flat and dead and does not respond to accelerator input - and you are sure the accelerator cable is correctly set to open the throttles 100% when you press it fully.
That means that you should either be hearing the engine bogging down (low fuel induction) or no response + no bogging which means that your spark advance is inoperative. For this you need to connect a timing light and measure the timing mark, you should see it advance as the engine accelerates.
Its best to check this without any spark advancer doo daa CNG thing attached. Remove it from the system, the pulse generator should work the ignitor which should switch the coil in real time. Many other carburettor Cultus owners have faced similar issues like yours.