As variously stated the pictured component is an EMI filter not a motor start/run capacitor. There's no reason to replace this filter unless you are having problems with electrical interference associated with the fridge operation. Additionally, as noted by @brhans, a motor start capacitor doesn't "boost power to a higher rpm", it just lets a motor run at its design speed (possibly multiple speeds if the motor is designed for that).
Domestic repair questions are better off in the Home Improvement site. However, is this fridge/freezer actually malfunctioning? Mention of a fan suggests this is a frost-free freezer. I have one myself (though not a Maytag) and the internal fan comes on automatically (presumably under thermostatic control) at various times. It also switches off when a door is open to stop blowing cold air into the room.
So what evidence do you have that the fan operation is actually incorrect? You stated it's working when the freezer is on so the fan motor is working. Are you sure that you are just not unfamiliar with the operation of your fridge/freezer? Did it have some previous pattern of operation that has now changed or is it new to you? Are the fridge or freezer sections failing to stay appropriately cold? Is the fridge/freezer in a location which is either unusually hot or unusually cold? (Some models need to be in a reasonable room temperature environment for their refridgeration cycle to work properly.)