I made an interesting discovery yesterday when I was setting the adjustments on the carburetors after installing new needle valves and adjusting the floats. When I had the idle mixture screws all the way in to do the initial idle mixture setting, I noticed that the springs were coil bound. I pulled one of them out, removed the spring and screwed it back in, counting the number of turns until it was seated. It took ten full turns. I then put the spring back on and screwed it back until it stopped and it was only eight turns, so what I had thought was closed is actually two turns open. Turns out that whoever rebuilt the carburetors for the previous owner installed the shorter, "new style" idle mixture screws in these 40DCOE18 carburetors. I'm going to shorten the springs until the proper screws, springs, and seals arrive.
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