Despite being very honorable men and believing slavery to be evil, Washington and Jefferson never freed their slaves while alive. Why didn’t they when other founding fathers such as Ben Franklin and John Dickinson did?
there's some great threads on the topic, especially Thomas jefferson (not much on washington specifically though)
https://www.reddit.com/r/AskHistorians/comments/3weqm5/why_did_thomas_jefferson_have_slaves_if_he/