Methods for modifying a ZSM-5 zeolite by contacting the zeolite with an alkaline solution prior to combining with a binder material to produce a modified ZSM-5 catalyst extrudate that has substantially longer catalyst life, relative to an untreated ZSM-5 catalyst, for converting light olefins to products that may be used as a liquid transportation fuel blend stock. The alkaline solution is optionally sodium hydroxide. The binder is optionally alumina, bentonite or silica.