I have a 1978 140 hp johnson that runs great at 3000 - 5500 rpms but at about 1200 starts to vibrate terrible. Am I losing a cylinder at low rpms? I am having no other problems with it and it starts up everytime. Any suggestions?
Between 1000 and 1600 rpm is the transition from low speed to high speed jets. Usually shakin' can be minimized with a proper sync and link.<br />Good Luck
