yeah rual if you reall y clean out your carby with carby cleaner and change your fuel filter ok if you have already done it once is fine, pull out all your jets and pins and clean every nook and cranny make sure you take every screw out dont worry about the butterflys just all the tunnels and stuff you will kick your self once you have done it .i had the same problem about six months ago it took me a month then i finally took my carby out and gave it the best clean i could and since then it hasn't missed a beat and good luck i hope it is as easy for you luckt i onlty have 55 horse two carby's only rooster

Hi Frank here,2 things you might want to look at.First make sure your timing base is moving at the same time you throttle up.Next make sure your carbs are not stopped up from old fuel.,like varnish in the bottom of the carb bowl.You may want to check and see if all your spark plugs are firing also.Try out these things abd I hope it will help you.