Hey guys im new to the site and mud motors in general i recently got a GD longtail with a 25hp kohler. the motor had been sitting for a couple of years i had to do some minor stuff like change the plugs oil and filters. Used amsoil on the fill up champion plugs and a wix filter. I can get the thing started runs great for about 30 seconds a little smoke but nothing out of the ordinary for a motor thats been sitting. Then it shuts off and the trouble starts. When it dies it just shuts off like the oil sentry switch activates or something. So i unplugged it still wont start. After it sits for about and hour same thing. I pulled the fuel shutoff solenoid it checks out. And then i dont know where to go after that. One added thing the regulator/rectifier has one broken prong the one closest to the ground. Thanks guys for the help. And another thing i dont think matters but i cut out the mercury switch.

Your carb might be all varnished up from sitting so long. Make sure your getting fuel to the carb, if you are make sure the float isnt sticking closed and not letting fuel in. You can try tapping on the float bowl to get the float to drop but if that doesnt do it you will have to pull the carb apart and clean it. I'd start with this