I changed the default value of the php max_execution_time setting from 90 seconds to -1 (unlimited) using the MAMP Pro (3.0.7.2) config file editor for php 5.5.18 (the current version I'm running). After running my script it errored out at 90 seconds. I changed it to 9999 seconds in case -1 wasn't supported. Same issue.
After outputting phpinfo() on the page, I see max_execution_time has two values:
Local value 90
Master value 9999
There are no additional ini files being loaded. No manual setting of this value in the code or in .htaccess.
Has anyone got any ideas? Even trying to override it in .htaccess doesn't work. Doing it in the php does... but that's not a solution. It should work off the php version config.