Remove carb from saw, dis amble carb. Watch how it came apart. Buy you some carb cleaner spray. Spray down outside of carb. Remove both high and low adjusters. Use red straw that comes with carb cleaner to spray threw both high and low adjuster holes. Spray threw every passage you can see in carb by putting the straw up against each passage and spraying threw each. If you have compressed air blow dry the carb and re assemble carb in reverse order you took it apart using new parts from kit. re-install high and low adjusters. Seat them being careful and just take them to where you just feel them bottom out, then open them 1 to 1-1/4 turn out and re install carb. The kit will come with two gaskets, two diaphragms, a needle, a spring and a arm. when re assembling the needle, arm and spring use a straight edge and lay across the two little blocks on each side of the metering arm and bend the arm to where the arm just touches the straight edge that you have across each block. This is for a SDC carb. I think the HDA, HDB and HDC carbs you lay the straight edge across the body of the carb. If you get on www.walbro.com website it will show you how to set the metering arm for each type of carb.
http://www.walbro.com/wp-content/uploads/2016/01/HDAseries.pdf
http://www.walbro.com/wp-content/uploads/2016/01/HDCseries.pdf
http://www.walbro.com/wp-content/uploads/2016/01/SDCseries.pdf
These service guides will help you. Brian
http://www.walbro.com/wp-content/uploads/2016/01/HDAseries.pdf
http://www.walbro.com/wp-content/uploads/2016/01/HDCseries.pdf
http://www.walbro.com/wp-content/uploads/2016/01/SDCseries.pdf
These service guides will help you. Brian