-----Go under the Small Engine Repair Reference Center (look for the wrench), then Marine/Boat Motors....you will click on MCCULLOCH in the columns and then click on 3-1/2.
You need to figure out if you have a Tillotson AJ or a Walbro LMO carburetor, then search Ebay or Google for similar parts. It can be a bit hit and miss, but lots of stuff are interchangeable. Eska Made the same design lower unit later using Tecumseh powerheads.
