Everyone who has a Dayton G73 or similar model needs to open the case and check the wiring from the thermostat. The thermostat is defective and is causing one of the leads to burn up.
See Mike Cruz's thread below with more pictures and how he ordered a replacement.
I have added a picture of mine below.
The serial number of the bad thermostat is: 5813-11002-000
DSCN0988.jpg