Too sugary-can I add more yeast?

I added a lot of sugar to a batch of cider-4c of sugar to 1 gallon, in hopes that the alcohol content would be higher. All I got was an OK tasting cider that is SOOO sweet it’s like drinking liquid diabetes! LOL! It’s been fermenting for 2 months. Can I add more yeast this late in the game to eat up some of that sugar?

It should be ok to add yeast. Are you sure there are no preservatives in the cider? Was it in a very cold place? Have you taken gravity readings to see whats happening.

dob