Engine NOTE: The F18A3 engine has been adopted. For the service procedures, reler to the procedures for F2021 engine. Refer to Shop Manuaâ€˜ 623N700 and 625N721 for (he ilems not shown in this section. For the service dam, refer (o the specifications in section 3 of this manuâ€” al. Ir Outline of Model Change The F18A3 engine type has been added.