Common problems with Marvin double-hung windows include a slipped clutch, strange noises or jerky movements when operating the window. Normal cleaning and maintenance eliminate many of the problems.
Resetting a slipped clutch requires turning the cam with a screwdriver and sliding the assembly so it matches the one on the opposite side of the window. Noises are often due to nails in the track that wear through the liner and require resetting the nail with a shorter one. Paint buildup sometimes causes a jerky motion of the sash. This problem requires removing the excess paint by sanding and refinishing the window.