My Powrflite has 2 mounting points for the Imperial
vac motors, so with lamb motors an adaptor needs
to be made up, the holes will not align without it.
You should have 3 large flexible pipes, 1 from where the
connecting pipe from the stack comes through to vac 1,
the second from No 1 exhaust, to the manifold below
vac No 2, the third from No 2 exhaust into the casing
of the machine.
I suspect either the motors are not squarely fittd on their
respective manifolds, or maybe the connecting pipe from the
stack through the pump/heating section is kinked or come off.
You cannot wire a vac motor wrong as it will spin correctly whatever
the polarity of the supply.