im haveing trouble with my throttle control from some reason forward works fine but when i put it in reverse it sounds like it grinding gears or somewhere alone those lines now this only happens when reverse is at losw but it works i got it out the water at checked it and it works just souns like its grind but when i put the throttke higher in reverse the grinding sound gose away where do i start so i can post what type of throttle i have or find a modle number or something thank you