Help support my channel by using the link. Ad https://www.amazon.com/shop/omfishing# On the 1991 Evinrude 30Hp. The components of the CD2U ignition system are flywheel, ignition module, charge coil, Ignition coils, spark plugs. The model number is printed on the module. CD/Capacitor, 2/ two cylinders, U/ under flywheel, S/ contains S.L.O.W. {speed limiting overheat warning}. L/speed limiting ignition module to prevent engine over speed. We are testing the module for intermittent miss or erratic running above cranking speed.