Obviously the wires are messed up.
At the rear of the powerhead, you will find a cable with two wires, coming up from the lower unit. There are rubber sleeves over connectors on the wires. Slide the sleeves back and disconnect the wires. Now, use a voltmeter to check the voltages on the (engine side) wires. Should have 12V on the green one when in forward, and 12V on the blue one while in reverse. No voltage on either when in neutral.
OK, if it passed that test, reconnect the wires and repeat the test. If you get funky readings, the cable going down to the lower unit is burned up. They don't make them anymore.
Under no circumstances should you run the motor with those connectors exposed and any possibility of them touching each other. It they touch while running, something expensive is going to bust.