I've got an 84 Yamaha 115 that runs like a top other than the fact that it will sporadically start missing, usually starts at high RPMs. You can back off the throttle, bring it back up and it will run fine for a little while and then start up again. Carbs have been rebuilt, new gas lines, new primer bulb, new fuel pump, gas tank is vented properly. I'd like to say that we have ruled out a fuel problem. Starting to think its electrical, possibly charge coils? Any ideas would be greatly appriciated!