  Faddeev-Yakubovski equations in configuration space are used to solve four
nucleon problem for bound and scattering states. Different realistic
interaction models are tested, elucidating open problems in nuclear interaction
description. On one hand, by example of nonlocal Doleschall potential, we
reveal possibility of reducing three-nucleon force. On the other hand we
disclose discrepancies in describing n+$^3$H resonance, which seems to be
hardly related with off-shell structure of nucleon-nucleon interaction.
