Home › Forum › Ask A Member › 1966 JW-21 3hp fixed carb orifice › Re: 1966 JW-21 3hp fixed carb orifice
Interesting that ME would chose to out that data on the ’66 model. The ’65 & ’67 models both show a 29D orifice show I believe we can be confident that it is a .029 diameter. Now these jets were not drilled rather reamed & flowed, but I think you would be safe to use a .029 or .030 drill. Just don’t spend any time wallowing the brass! Your problem may not be the hole rather the area behind the hole. If it is gummed up the jet will not flow properly. Have you let the bowl seat with Engine Tuner over night? That stuff is very effective at removing the most stubborn gum & varnish. I have all of the orifices new for replacement if you could just get it out? If you get desperate enough, clamp the bowl to a 2X4 & hold it in your drill press. Drill the orifice out (it is 1/4 X 20 threads). Leave enough for a small ease out to remove the hull of the orifice. I can send you a new jet. I have done this many times on both aluminum & plastic bowl carbs!
Dan in TN