Can Somebody Please Advise? My Son Has A 14 " Jon Boat With A 2007 15 Hp Johnson Tiller. Well Maintained And Lubricated Regularly. Our Problem Is The Throttle Will Not Return To Idle Automatically,we Must Twist Back To Idle. Is This Normal? My Fear Is If Something Were To Happen And He Had To Let Go Of The Throttle It Would Stay At Same Rpm.thanks Ralph