For a four cylinder vertical engine, the commonly used firing order is July 28, 2021 by admin Question: For a four cylinder vertical engine, the commonly used firing order is A. 1-2-3-4 B. 3-4-1-2 C. 1-3-4-2 D. 4-3-2-1 Answer» c. 1-3-4-2 Note: The above multiple-choice question is for all general and Competitive Exams in India.