I am working on my dad's boat, it's a 1975 Mecury Thunderbolt 500 50HP outboard SN: 4144800. It has dual Tillotson KA26BT Carbs on it, and it just wasn't making any power. If i sprayed carb cleaner in to the top carb while it was running, the rpm's and power came back to normal, so i bought some carb rebuild kits and tore them apart. my problem is that the idle tubes on both carbs are cracked, and i can't seem to find anywhere to get a replacement. Mecury lists that the idle tubes only come with the new carb assembly, and it's so old, i obviously can't get that. I have even called tillotson, and they list the idle tube part number as 16865, but that is not available from anywhere either. Is there anywhere to source replacement idle tubes for these carbs? I would even consider just replacing the carbs with something newer. Maybe there is something that will just bolt on from a newer model engine? maybe someone has some parts laying around that they can sell me? Anyone have any ideas?
Here is a picture of the worst crack in the idle tube:
Here is a picture of the worst crack in the idle tube:
