Have you cleared the cache on your browser? If not try that, if you have and the problem persists and WeeWX restarts with the same simulated data then almost certainly the database file was not deleted. Which file are you deleting? It should be /home/weewx/archive/weewx.sdb. I suggest you stop WeeWX, delete the file, verify it was deleted by displaying the contents of /home/weewx/archive and then restart WeeWX. If the problem persists post a copy of the WeeWX startup log from when you restarted WeeWX through until at least one archive record is saved to database.
Gary