Question on a White SnowBoss 800 ST snowblower. When I ran this in preparation for the season it ran fine. When I used it Saturday night and Sunday it would only run with the choke about halfway. If I took the choke off completely it would die. Could this be caused by the low outside temps? It ran fine as I said during prep when it was 50-60 degrees. This weekend it was no more than 15. Can't remember ever having a problem with it in the cold although this was colder than usual. Any thoughts or suggestions?