Starting

1982 Nissan 280 zx just started this issue. Sometimes will not start until cranked for quite some time. Problem usually occurs more after the car has warmed up but has happened once after being driven for an hour then sitting for three hours and wouldn't start until battery went dead and a jump was supplied. I believe there is fuel as on the forementioned occasion I discovered a small leak on the infeed line to the pleneum. Tightening said hose did not affect the problem. The last occurance was after the car was driven approximately two miles but was warm due to previous use. It then would not start after sitting for about 20 minutes. I left the car sit over night and it fired right up the next morning. I am lost as to what to check first. The fuel system or the electrical system.