Wav 50 motors, even new don't perform well, if you look at the brushes, you'll find mayb, only part of the brush working. A good motor reconditioner that uses harder compound brush, will improve things, otherwise remove motors, remove brake, attach a drill, and using chalk bed in the brushes.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.