2004 115 yamaha 4 stroke....starts / idles perfectly...... vibrates / rough 1600 through 3200 rpm....smooths out runs well 3200 too 5200 rpm...changed out prop but same problem....has 1000 hours well maintained...have had injectors / ast chamber cleaned several times in past to fix problems with not ramping up to 5200 rpm but motor has never vibrated like its missing or something before...has new plugs / fuel pumps .....what to do?
