IH 154 Carb technical question

[John in Ct]

My IH 154 Cub Lo-Boy runs good but I have noticed the carb gasket is always a little wet . I know about the top half of the IH carb warping. My IH top is from a regular Cub and at one time, it was milled pretty good to get it flat and The idle tube # 251 331 R1 was shortened too ( not by me).
I took it apart today and put the top half back on WITHOUT a gasket to see how the fit would be and found that the idle tube # 251 331 R1 was keeping the halves apart. The distance apart was close to the gasket thickness. I was thinking that the idle tube # 251 331 R1 is still too long and that I should shorten it even more. I am not sure how long the idle tube should be taking into account my milled top half. Should it touch the bottom of the hole? Also, what drill bit is the ID of the idle tube # 251 331 R1 in case I need to reem it after cutting? Thanks!!

[Bigdog]

John - first of all, be aware that there is a small orifice in the threaded end of the tube so if you cut it and try to clean out the inside with a drill bit don't go down too far. I have seen tractors running without the idle tube even in place so I don't think you will create a problem by taking a small amount off the tube. I would think .030" to .040" would be plenty as long as that gives you enough distance with the gasket in place.