Was your snow blower covered?
If not it could be just rust around the pull cord winder assembly, I have seen it a thousand times.
WD40 will work wonders if that is the problem, (or Moove-it) let it sit, then work it. Using the wrong gas will only cause a problem, if you left it in all year, and then got it to start this winter, so don't worry.
EMPTY THE GAS at the end of every season.
small engine mechanic, December 2008