Having used both H/W and C/W carbs from Tom Langdons Stovebolt Engine Co. (586) 739-9601 I found that you have to be a little careful when you bolt the carb to the adaptor. If you try to force the fit you will possibly have leaks. I found that if you drop the four bolts with a small washer pointing DOWN in the elongated holes in the adaptor,then coming up from the bottom, slide on the 4 hole gasket and set this assembly on the inverted carb. You may have to wiggle it around to get everything to seat properly. The key is to get the entire assembly together so that it is a LOOSE fit before you spin on the nuts evenly.
The H/W is a rebuilt carb while the C/W's are new. If you're unhappy with the carb condition I'm sure Tom will bend over backwards to correct the situation. A worn throttle shaft is not something he would expect you to accept. However, I would go through the bolt-up sequence again and see if that doesn't correct the problem. All three of my carbs from him were awesome right out of the box. Hope this helps.
Dave
