I'd start by setting the radio to the expected receive frequency and
seeing if it can hear your other radio.
It is possible that, due to spurious outputs, or front-end overload, the
scanner picks up the lower frequency signal before it gets to the
expected frequency. So the first step is to make sure that the signal
sounds clear on the transmit frequency.
Another problem with transmitting on 146.7 is that, if the HT has
Automatic Repeater Offset, it will actually transmit on 146.1, expecting
that it is working through a repeater with a 600 kHz offset. In that
case, try running the test on 146.5 instead, which should be in the
simplex segment.
I'd run the test on the lowest possible power from the HT, and with
a dummy load or attenuator on the output rather than an antenna.
(And possibly a dummy load on the receiver as well.)
It is easy to overload some receivers and generate a lot of extraneous
signals.