A power generating apparatus includes an engine for driving a generator; a fuel tank for storing fuel to be supplied to the engine therein, and a canister containing an adsorbent for adsorbing thereonto fuel that evaporates from the fuel tank to inhibit release of the fuel vapor into the atmosphere. The canister includes a communicating tube, which places the canister in communication with the atmosphere. The canister is in communication with an intake system of the engine. The canister is positioned proximate an exhaust system of the engine to improve the purge characteristics of the adsorbent so that a usable life of the adsorbent is increased.