Har to believe that I started this "project " 7 years ago and still haven't finished it. Moved 3 times including having 2 houses built and then buying a third and spent 3 years renovating it. That said, I'm nearly at the point of breaking out the project and getting to work on it finally.
Z13phil got me thinking about the freaking pilot circuits again. How many times have we discussed this topic to death!! This time Z13phil mentioned that he is going to put a fuel pump on his beast in hopes of curing a long time fueling problem. He also mentioned about float level settings which caused me to pull out my rebuilt carbs that I had done 6 years ago and have another look at them..
I decided to pull them apart and see how they faired being in storage for such a long time and I also wanted to use the "Scotch's cleaning tool" on them. when I originally rebuilt the carbs, the cleaning tool was "in development" and not available at that time. i have since acquired the tool and have been looking forward to using it to see how much more crap can be removed from my rebuilt spotless carbs.
So I started with tearing down the 5-6 carb. All the carbs look great considering they've been boxed up. After tearing down the 5-6 carb, I started reviewing the pilot circuit, passage by passage and getting my head wrapped around the flow of fuel and air in the circuit. Flashlight in hand, check this, check that and then WTF??? Looking down the fuel supply port passage in the #5 main jet/emulsion tower, I see that the passage was not completely drilled out where the angular passage meets the vertical passage. Now that being said, the fuel flow through that blockage will still feed the orifice in the pilot jet so as far as consequences goes, it's probably not a big deal, but as far as cleaning/clearing the passage of debris, probably not as good as a clear passage would be. So I'll get out my number drill bits and a pin vise and clean out the burr that was left from the original machining and then carry on flushing with the cleaning tool.
When rebuilding carbs, attention to detail. Don't be afraid to use a flashlight and a magnifying glass or at least put on your reading glasses. Check, check, check!!!
Pic of the Main Jet/ Emulsion Tower
Pic of the #6 pilot fuel supply passage in the top of the tower showing what is a clear passage.
Pic of the #5 tower showing the incompletely drilled passage leading to the vertical passage.