Learning activity packages are presented for instruction in tractor mechanics. The packages deal with the duties involved in maintaining the fuel system. The following fourteen learning activity packages are included: servicing fuel and air filters, servicing fuel tanks and lines, adjusting a carburetor, servicing a carburetor, servicing the intake manifold, servicing the governor, servicing the fuel pump, servicing the diesel fuel filters, servicing the diesel transfer pump, servicing a diesel injection pump, servicing a diesel fuel injector, bleeding the diesel fuel system, timing a fuel injection pump, and servicing a turbocharger. Typically the packages' format contains introduction, directions, objectives, learning activities, tools and equipment needed, supplies and materials needed, safety, instructions, student self-check, check-out activities, and the instructor's final checklist. The packages are illustrated. (CSS)