I put a mixture of oil gas in my 621 R/621 toro snowblower?

Drain the tank,clean tank,remove bowl under carb,one screw holds it on,gas will spill out,have some rags around the area to catch gas,wipe out,put back on,then fill with gas,check spark plug if you tried to crank with bad gas.Also make sure your air filter is clean.If you can put a inline fuel filter with a on-off switch on.

Hi Jerome:
Shouldn't be too bad.
You could disconnect the fuel line at the carb and drain the tank.
Drain and flush the carb. Reconnect the fuel line and fill with fresh gas.
If it won't start, pull the spark plug and clean/dry it with a propane torch, or replace it.
Odds are it will be fine.
Cheers.