Take a look at temperature stripping: Thick or weakened weather stripping can reduce limited closure; trim or change as wanted. 1. Find the limit adjustment screws: These are often located about the side or back on the opener motor unit. The Chamberlain Whisper Drive comes with a 1/2 horsepower motor, https://youtu.be/wSkWTAdm-Gg?si=pR5EXdjVuNYjtHN7