where can I find a 2-Stroke DTX 23 cc Gas Engine for a fire hammer

You should try the Giant scale forum.

Guess you already did and received a reply.

You should really stop posting the same question in multiple forums

Approximately 2 seconds to search for duratrax's home page on google. 30 second to find the right part, and about 2 more seconds on google with the part number to find what hobby stores carry it. Of the three I checked they all had the same price. You will notice on the parts list that you can buy the engine internals, so if your whole engine isn't ruined, you may be able to get away with re-building it.

Moral of the story: Get good with search engines, and you can find anyting with Google and two minutes of free time. Anything.

Here is a link to the engine:
http://www2.towerhobbies.com/cgi-bin...?&I=LXHKV2&P=7

Here is a complete parts listing for your car:
http://www.duratrax.com/cars/dtxd97d.html