I had the same issue, this is how I worked around it:
Upload the component to the tmp folder in your root directory via FTP
/public_html/tmp
Then in the Joomla backend, extension manager and instead of choosing file to upload, put the path to the file in the "Install from URL"
www.yoursite.com/tmp/com_filename.zip
Click on Install and it will grab it from that folder and install it without issue.
This is true with any file that is over 2 meg
Hope this helps
Troy