with the thermostat out water will discharge out the exaust port.boat dealership told me its ok to run without thermostat in summer but not in winter,so put the thing back in last weekend, no water discharge anymore. motor did allright all day no over heating or cutting off,so i dont know what to do now. oh spaz my motor was hard to get up on plain i cleaned the carbs,new plugs,ran seafoam through it,and changed fuel tank and hose, after all summer it finly started running good, seems like ever time it strugled getting up on plain the ball had lost presure,keep eye on that hope it helps, fishhunter