How to see entire job step output?
In the job step advanced properties, send output to a flat file by inputing the "Output file" location and filename.  That should include all of your output for later viewing.  

Or, if you want all of the output directly in the history of the job, you can select the check box "Include step output in history".  It'll use history entry rollover to include all of the data.  That might be a little cumbersome in looking at after-the-fact, though, but still effective.