jonathancassar:

42etus is right on the money. Always, always follow the manufacturers break-in and running instructions. Who would know the most about their engine? After breakin, get the hs needle a little rich and leave it alone unless there is a obvious problem in keeping it on the rich side. This is a great engine that deserves TLC and will give you years of enjoyment treated correctly. Do not forget to adjust the valves once in a while. Should take you around 5 minutes once you get the hang of it, but do it right. Dont want to teach anyone bad habits, but of my 4 YS engines currently in use none have seen anything but 15% Powermaster. Don't do this until you have a very good handle on the engines and can tell what they want. If you can afford the 20-20 fuel, stay with it. Keep a good plug in her, OS 4F. Starting and running does not mean the plug is good, just that its working. Tired plugs seem to be the most frequent problem you will run into. I see a lot of sniveling about the YS engines on the net. The engilnes are outstanding, well above others and perform that way. Usually the problem encountered with these engines is the nut screwing on the needle, refuses to read and follow instructions and plays with the needle each and every run, and snivels on our forums that the engines are junk due to his incompetents. ENJOY