first no luck with first posting!I replaced my bad 1982 john/omc 115 o/b with a new 140!Change l/h jets,plugs,oil,and even stater.Moter power aswom!2 houres with twice oil mix.Will literly snap neck.But at constent rpm has a viberation like a miss and tack jumps from time to time.After 2 houre pass buy a 5000 rpm for 5 sec!ran aswom.So after 2 houre brake in vibe did seem to get less but still there.ANY CLUE!3000 SEEMS TO BE WORST 