I'm not sure there is a max value. How many values are you trying to show? I'm able to display 52 values in a drop down search field in the project that I'm working on.
Maybe confirm that there are no Xpath constraints on the drop down that will be making the list smaller.
Austin's suggestion is a good one. Also, you could check permissions on the target entity as that could also limit the values you see.
You may want to consider one of the search widgets in the app store. 1185 items in a drop down is probably not usable...even if you type in a few characters, you still won't narrow down the list enough to provide an efficient searching capability for users. I really like the Data Grid Search Filters. Alternatively, you could make this a comparison search instead of a drop down.