Re: NGK BP6HS-10 Spark Plug
Your oil ratio is what is causing your problems. Do some reading here and you'll see that the 16:1 ratio is too much oil. You'll have spark plug fouling problems as well as muffler/exhaust clogging issues not to mention overall poor performance.
Reduce your oil to fuel ratio to at least 24:1 or better yet, 32:1. I think you'll see better performance from your engine. Also you need to put some miles on it. 200 to 300 is what has been found to be the point where an engine is considered fully broken in. Don't worry too much about how it runs until it gets some miles under its belt.
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