According the Github, the tutorial about to configure the Federated Search is homologated to Portal for ArcGIS version 10.2 (https://github.com/Esri/geoportal-server/tree/master/components/server/FederatedSearch). If the configuration is applied to the version 10.3, the federated search does not work.
To resolve this problem it is necessary to edit the file "federated-searches-json.js" that is within folder "custom". It is simple, just removing the prefix "esri_" from the IDs, at lines 87 and 89.
var targetNode = dojo.byId("arcgisonline_sharing_dijit_SearchResultsSimple_0");
var targetHeaderNode = dojo.byId("resultsLabel");
var targetSortersNode = dojo.byId("arcgisonline_sharing_dijit_Sorter_0");
This is necessary because the Esri's page changed some IDs of HTML elements. After this the federated search works.
Sorry my English!