My friend has a 25 h/p go-devil with a kolher command engine.
The thing sat up for about a year. Put it in the shop to get the carb rebuilt and doing so they said that the fuel shut-off switch was bad so they changed that as well. the motor runs fine when it is not in the water 3500 rpm. when you put it in the water the boat dose not get on a plane and it still runs at 3500 rps. it is on a 14x48 flat boat. He also told me that when he pulls off the spark pulg wire off one side it kills the motor , and when he dose it to the other side it still runs.
Thanks for any info u can give us.

Thanks found the problem. It was the coil.