Bezirk wrote:It does have an effect on the performance of the engine, however on my first Cub the tube was broken and missing from the carb. The engine ran and at Boss Hogs fest I learned that it was supposed to be there. I got more info from the guys at the fest and Bob from Ct. went to his car brought me a tube and would not accept payment. Ths was my first lesson about the generosity of the good people at the Fest. I drilled out the old tube rethreaded the hole inserted the new tube and it has run fine for several years now.
Berlin
Berlin, I don't think that was me but I'll gladly accept payment for it now.
Idle tubes are not too bad to replace. Many, like one of mine, were broken by neophytes that did not expect them to be there when splitting a carb for the first time. You can buy one for about $15 from Macdonald carb & ignition. It you need a tap, it is a
4-48 thread, not the more common 4-40. A left twist drill is the cat's meow for extracting broken parts. The 4-48 tap drill is #42 so I would use something smaller that that (higher number) as an extractor and you may not need to re-tap at all.