A professional who fits together mechanical parts at workbench or assembly floor to make subassemblies for internal combustion engines according to drawings or routing sheets, using handtools and power tools. Responsibilities include:

• Places basic part of assembly, such as carburetor, water pump, fuel pump, oil pump, governor, cam housing, gearcase, exhaust housing, remote control, pistons and connecting rods into holding fixture.
• Bolts, screws, or pins mechanical and electrical parts together, such as push rods, valves, rocker arms, and magnetos, using power wrenches, torque wrench, stud drivers, and hammer.
• Operates hand or power arbor press to press bushings and seals into housings or onto shafts.
• Reams tubular worm gear cage to form smooth surface for assembled worm gear, using hand reamer.
• Tests sealed units, such as relief valves, fittings, and cylinders under air or water pressure.
• Applies decals to engine to indicate operating procedure.
• May be designated according to part assembled as carburetor assembler; cylinder-head assembler; gearcase assembler; governor assembler; remote-control assembler; water-pump assembler.