Diesel like all gas is derived from crude oil, comes off well before gas in the cracking off process. It has a little more BTU's per unit of fuel and weighs almost a pound more per gallon. Just because a diesel doesnt smoke most definitely does not mean there is a problem at all. Quite the contrary in fact. You are running clean, cool and have a well designed diesel. The new diesels from International, Cummins and Isuzu exhibit very little smoke. They are atomizing fuel better and using sensors to adjust the diesel injection amount depending on enviromental factors such as altitude, temperature and load. Unlike gas engines that run hot on a lean mixture, diesels will run cool on a lean mixture. If you run to rich a mixture in a diesel it will overheat the exhaust sytem. Smoke on Shibura (sp) the engines New Holland buys and puts in their small tractor engines seems to be a inherent. I have a 2120 that smokes a bit under a load. It does not bother me except for the smell. The loader is discolored from the smoke. In the very near future I am sure restrictions on the emissions from tractors will come under tighter EPA regulation.
