When I did mine I only changed the little O-ring. I did an internet search and found out that some BMW Motorcycles used it on their Carburators; and there is a BMW Motor Cycle Dealer not far away. So that became my local source.

Lift Supply/Sump O-ring from BMW motor cycle carburator
BMW motorcycle parts 5x1.5 O-ring, cold-start enrichener shaft, part# 13 11 1 257 819

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84 300D, 82 Volvo 244Gl Diesel