does the part which came off fit back in or is it to tight to fit, reason i ask is i actually saw a carb body listed in spares section on a site yesterday while i was looking for bits for mine, so wondered if you were to strip your carb body and hsn assemblies right down so you are left with the 2 blocks maybe if you heated the carb body and froze the other section you may be able to fuse them back together again, just an idea as it seems this is how they are assembled at some point anyway, you may get away with it?? nothing to lose i suppose