Sears Chainsaw sharpening

Husqvarna 42 cut, 18.5 BS single cyl, 05 model, 98 hrs, will not run unless choke is on and will not idle. Backfires and is using some oil. Smokes out of the fuel pump and muffler, any ideas on diagnosing this problem will be greatly appreciated. Thanks

My older Echo blower was not coming up in RPM; the shop suggested the possibility of a blown gasket...I purchased all the gaskets, new plug including piston ring, needed to rebuild the engine completely and did so. It will now not start and I am wondering if there is some timing issue that I am not aware of...I have been told these simple 2 stroke engines do not need to be timed but I do not seem to be getting a spark at the end of the sparkplug lead but have continuity from the switch to the end of the lead. What is the best way to determine if I have adequate spark and the magneto is working? Fuel seems fine...and I positioned the piston head arrow toward the intake side..anyone offer some help??