We present a measurement of the top quark mass with t{bar t} dilepton events produced in p{bar p} collisions at the Fermilab Tevatron (√s = 1.96 TeV) and collected by the CDF II detector. A sample of 328 events with a charged electron or muon and an isolated track, corresponding to an integrated luminosity of 2.9 fb−1, are selected as t{bar t} candidates. To account for the unconstrained event kinematics, we scan over the phase space of the azimuthal angles (?{sub {nu}1},?{sub {nu}2}) of neutrinos and reconstruct the top quark mass for each?{sub {nu}1},?{sub {nu}2} pair by minimizing a?2 function in the t{bar t} dilepton hypothesis. We assign?2-dependent weights to the solutions in order to build a preferred mass for each event. Preferred mass distributions (templates) are built from simulated t{bar t} and background events, and parameterized in order to provide continuous probability density functions. A likelihood fit to the mass distribution in data as a weighted sum of signal and background probability density functions gives a top quark mass of 165.5{sub -3.3}{sup +3.4}(stat.)±3.1(syst.) GeV/c2.