I finally got around to checking mine today and it was loaded with soot or carbon or whatever, even the tail pipe before it. In the manual for the RTV1140 it was called a spark arrestor, which I thought was stupid with a diesel. I got to thinking about it and remembered back in the early '70's I drove an old FWD water truck for a mining co. in Az.. This was a new open pit just starting up and we had to haul the water from the bottom of the hill up about 1K ft. at a pretty steep grade. Going up that hill with a 4000 gal. tank of water got that old truck warmed up pretty good as it just had a straight pipe coming through the hood.There would be flames blowing 3 ft. in the air on the steeper grades.
This memory lead me to clean up the spark arrestor and put it back on. I really don't think that this little engine, with a muffler and all, would ever get close to that hot, especially the way I use it ,but better safe than sorry.
Thanks for reminding me.