Hi Graeme
It's been sitting for a fair period I would say. I couldn't see the pictures but I would say your best bet would be to source a good second hand tank and return the carby to original. The diaphragm will be unserviceable for sure. The filter screen on the end of the pick will most likely be blocked. The last rusty tank I had cleaned up OK after putting a handful of small blue metal in it with water and agitating for a period. If the filter screen is badly gunked up and the deposits have set hard I find the best remedy is to sit the screen in a small bowl of CLR clear and leave overnight or longer if required. The screen will be spotless.
Not an out of the box suggestion but I do think it will save you a lot of time.
Cheers
wce
