Experiments using a 48Ca beam on 238U and 242Pu targets to produce superheavy nuclei were performed at the gas-filled separator DGFRS-2 online to the new cyclotron DC280 at the SHE Factory at JINR. The decay properties of 286Fl and 287Fl, as well as their α-decay products, were refined after the detection of 25 and 69 new decay chains, respectively. In addition, 16 decay chains of 283Cn were observed in the 238U+48Ca reaction. The possibility of existing of isomeric states in the 287Fl consecutive α decays is discussed. A new α line with an energy of 100–200 keV lower than the main one at 10.19 MeV was observed for the first time for even-even 286Fl decay. A maximum cross section of 10.4+3.5−2.1pb was measured for the 242Pu(48Ca,3n) 287Fl reaction.