Hi guys, having problems with the running of the motor, seems to be missing kind of, runs mint up a hill or under a bit of load, or to start with, then once up to speed its seems to be going from the sweet sound to a rough sound, I've checked the carb, all good there, plenty of spark, plug is black though, I'm thinking it could be my mix or the oil I'm using, it's been the same from when I got it really, just seems weird that's it's at mid to full speed, but more often it's just like it all the time from go to top speed. .....
Doing my head in....
HELLLLLLLL.LP