For Schedule C, there is not a specific section set aside to
handle fuel costs for business equipment such as what you described.
In order to keep track of it for your own benefit on your
return, it might make the most sense to list the diesel fuel cost on its own under
the Less Common Expenses section,
using the Other Miscellaneous Expenses
category. Doing so will allow you to
enter your own description for the expense so that you can categorize it any
way that makes sense to you.
