Hi kevbar. As background, here is the workshop manual for your saw:
http://www.getsaws.com/PDFs/w9600001.pdf
Here is the workshop manual for its Walbro HDA35 carburetor:
http://wem.walbro.com/distributors/servicemanuals/HDAseries.pdf
My initial guess as to what is causing your problem is a mild case of flooding, which becomes insignificant when the engine is running. The cause of flooding with that style of carburetor is usually to be found in the metering chamber, and in most cases, either the metering lever is set too high or the metering diaphragm is misassembled.
I suggest you set both mixture screws for 1.25 turns from fully in (be very gentle when bottoming those screws), go back to the metering chamber, and review your work there carefully, using the manual as a reference.
If the problem is not in the metering chamber, it seems likely to be a case of damaged mixture screws due to overtightening when locating the fully-bottomed position. You can usually find this problem by inspecting the taper on the tip of each screw with a magnifying glass, looking for deformation or contact marks.
