Before you start dismantling the fuel system you need to understand what happens to allow fuel into the engine. You can remove all of the supply part of the system by attaching a line to the carb from an alternative supply. this can take the form of a vented bottle with a tube connected to the carb which allows fuel to flow directly without vacuum valves, filters, pumps etc. If the engine runs with this connected you have saved yourself a carb strip and have narrowed the search to "pre carburettor" supply system. Remember to do this outside and have an extinguisher available as in all fuel system fault finding.
Cheers now
oldgrubber, February 2019