Have put on about 100 miles. Ran like a top. Now, it takes forever for it to start and when it does I have to keep it at full throttle, but will eventually die. I looked at the sparkplug and it looked dirty but not clogged. I've been running with a high oil to gas ratio(like the manual said), and thought this might have caused the fuel line/filter to have clogged prematurely. Does this sound like I'm on the right track?