Review on 🔌 CDI Switch Box 2pcs for 50-275 HP Mercury Outboard Motors | Power Pack 332-7778 18-5775 Compatible by Zach Peterson

There are several of these models on the market and this one is exactly the same as the OEM CDI. It may have a slightly different trigger threshold, but the timing didn't change by more than 1 or 2 degrees (cut off with a screw on the motor). I put it on the table with the scope pointed at the motor and it works just like the OEM. The trigger inputs have a diode that shorts the negative side to ground, converting the trigger to a positive 0-8V pulse. The output connects a charged +300V capacitor to the spark coil. It doesn't charge a capacitor through a coil like some other aftermarket CDIs did (they might work, but it's different from Mercury).