Designing the mechanisms of modern machines is a complex process, where the stage of structural analysis is a priority. When there are a plenty of redundant links in mechanisms their load capacity and efficiency are reduced, increasing the requirements for the accuracy of manufacturing and assembly. It is desirable that mechanisms not requiring high torsional stiffness have no excessive connections; they should be self-aligning. With the advent of new multi-link spatial mechanisms, the task of creating mechanisms without redundant connections becomes more complicated. The structural analysis of the rhombic mechanism of the Stirling engine with a advanced connecting rod of the working group, carried out by the graph method.