Teaford........there are 4-common runtime issues with the N-Engine.
1) runs fer about 1-min and quits; restarts innna'bout 5-mins; BAD condenser....NOT yer problem as stated
2) runs fer about 1-hr and quits; restarts after 4-hr cool down; BAD squarecan ignition coil; NOT yer problem
3) runs fer about 15-mins and quits; restarts after'bout 30-mins; BAD weaksister ignition switch, could be yer problem; NEW ignition switch ($10, cheap)
4) runs fer about 5-mins and quits; restarts innna'bout 5-mins; CLOGGED in tank fuel filter. sound like yer problem??? You will haffta un-screw yer glass bulb valve to clean the 2-tubes attached to the glass valve assy.