I just replaced a briggs and stratton 12hp engine with a 14.5 briggs and stratton ohv the wiring was a bit different and had an extra harness that could be unplgged it seemed to only run power to an anti backfire switch connectetd to the carb where the needle valve was anyway the engine roles over fine but there seems to be no spark what could be causing this?

The extra harness to the anti backfire solenoid not being hooked up will keep the engine from starting.

the extra harness to the anti backfire solenoid not being hooked up will keep the engine from starting.

Thank you for your response I actually figured out today that I had hooked up the little black wire from the coil improperly shorting it out and not allowing for spark the harness was not needed because I replaced the solenoid with a needle valve. So for anyone else with this trouble hope this helps