carburetor on 14.5 ohv Briggs?

I started an engine upgrade on my simplicity Hydro 12 tractor. It originally had a 12hp briggs and I upgraded to a 14.5 ohv. Here's the problem I'm running into; realized that both engine had different carburetors, and the engine I have now has a carb with a solenoid. I've checked online to see if anyone has ran into the same problem, but haven't had any luck. How and where would I wire the solenoid into for power?