It's normal on most Powertorque Victas to rev higher again as you go through the start position before stopping it. That's to help it start easier in the start position.

I have had the problem of the motor backfiring as you shut it down. It turned out to be the decompression valve. After replacing it with a used one the problem went away.

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!