50hp no spark to both plugs

First, do not use the spark plugs to test for spark. They could be fouled. (another lesson) use new plugs or a spark tester, This a HOT (powerful) ignition system so be careful. Test for spark. No then, find the black wire with the yellow tracer is the ignition kill circuit, (or it was, should still be) I would disconnect it from the ignition switch and test for spark. Do not touch this wire during or after testing, it will hurt. if you have spark, ground the wire back to the terminal to discharge. You probably have a bad key switch. more if this does not work