Clueless123

Hi all, Hope someone out there can help. My son got two F1 Carrera cars for Christmas but they are not running properly on his Scalextric track as they appeat to jam if going slowly. Should I be filing the guide blades down or what? If so, should they be narrower or shorter or both? Would love some help as currently have a very dissappointed child in the house. Thanks in advance.