410,
I'm using GMail successfully via IMAP in Outlook 2013 under Windows 8.1. My settings are:
Server Information
Account Type IMAP
"Incoming Mail Server" imap.gmail.com
"Outgoing Mail Server" smtp.gmail.com
Then under "More Settings":
Outgoing Server Tab
"My Outgoin Server (SMTP) requires authentication" is ticked
"Use same setting as my incoming server" is selected.
Advanced Tab
"Incoming Server (IMAP)" is set to Port 993
"Use the following type of encrypted connection" is set to SSL
"Outgoing Server (SMTP" is set to Port 587
"Use the following type of encrypted connection" is set to TLS
I have no problems with these settings. Hope it helps.
Messy