Starting Issues Seadoo Speedster SK Jetboat

[ryleland78]

Pulled the jetboat out of storage last week, and tried to start, but would not fire on the port side. I talked to a marine guy and he told me it may be a switch box. So I ordered a new switch box. I disconnected both of the original oem sealed switch boxes, but stopped when I noticed each switch box are twinned together into the sealed unit. So I put the wires back based on the colors. I found a wire off of the rectifier, reconnected and I now have spark on both sides of the 210 Merc. Now my issue is whenever it tries to start it backfires very loud. I primed both side of the cylinders with a bit of mixed fuel and it starts, but back fired again. Would I have reversed the switch box wires and it is misfiring? There was a white wire coming from the switch boxes up to the stator or trigger that was twinned together.

Is there a wiring diagram of the switch boxes to make sure it is all correct? I really need some direction as I am now lost...