carb question

[maxco]

So my machine is blubbering and buring a ton of gas in the low/midrange.
plugs are black and greasy. rich yes I know. I need to adjust the needles. I would like to move one full e clip, but caution is telling me move one shim at a time. I do not have much snow left, maybe one mechanics run. I would like to have this work. right now it is 3rd slot down. one shim on top one on bottom. If i put two on top.(droping down to lean) will it make a significant difference? it seems really rich. my low-mid range (5500-6000) gas mileage is terrible.full speed plugs look good. carboard colored,whitining tip, oil three rings down. I have AAen carb tuning book, and have done carb work, but not much real world experience with dropping jets and their effect. thanks guys.

 

[snowdad4]

mrviper did a good write up on how the needles affect carbureation. try a search and see if you can find it.

beyond that, your on the right track for the midrange with the needle adjustment, assuming the pilot and main jet circuits are close and correct. and as you know by now, test, test, test. and if unsure, half setting at a time are good starting points if your testing. it is a pain to access the needles but after a few attempts becomes easier. fabricating a long reach ball end allen will be a time saver.