The McCormick 3680178M1 is a genuine OEM starter motor rotor designed for reliable performance in agricultural machinery. This essential component measures 105mm in length and 54mm in diameter, featuring 9 teeth for efficient engagement. It is compatible with a wide range of McCormick, Massey Ferguson, and Landini tractors, ensuring proper starter function. This rotor is also cross-referenced with Massey Ferguson 3680178M2 and Perkins 3680178M1, making it a versatile replacement part.