hello iI have an older suzuki spiirt 85hp outboard I think it's a 1979 model it runs perfect starts at the click of the key idles and runs perfect when hooked up to the hose with earmuffs on it. But when im on the lake it runs good until i trim the motor all the way down when ideling . then it always quits . if i trim it up a little while ideling it keeps running fine . it runs good all they way down when your moving but at idel it always quits . what could cause this