Just purchased a nearly new BME 50 that had previously had around a gallon though it. Im running a 22x8 menz prop on 50:1 Sthil oil. Looking at other posts, I see that people are getting 7000+ RPM on this prop, but mine max's out at around 6400. Initially I thought that it could be overheating, so I removed the cowl (no better). I've checked the system for leaks and can't see any.

Something else thats bothering me, is that the engine doesn't seem to prime itself when choked, but a quick squirt of fuel in the carb and she'll start first flick and draw fuel.

Any suggestions?

Thanks in advance