Gentlemen, Firstly, I simply have to apologize- I neglected to mark my thread for watching and I have missed out on all of the great advice here. Sometimes I forget that on this forum, one needs to mark a thread for watching. I did mark a related thread and it somehow got into my mind that that is 'the thread' about my tapping task. Only now was it brought to my attention that I have this thread going. Again, please excuse me.
So, not having had the benefit of the advice from you guys, I went forward and tapped the existing holes for 1/4" x 20 tpi. Luckily, it actually went ok. I drilled the clearance hole out in the air horn, and then I went directly to tapping the float bowl. There was no need to use a tap drill -the hole was well stripped and seemed perfectly ready to take the 1/4"-20tpi tap. I put in the new bolts and it seems really good. However, reading now your responses, I suppose I was more lucky that smart. Now I just have to re-install the carb and see the result. Thank you, gentlemen!
Last edited by Alden B.; 12/15/2014 6:24 PM.