Put a temp guage on it...

The head temp should be around 300 degrees at WOT.

If it's higher it's too lean.

It tends to run hot until it's broken in fully, so do not be afraid of richening it out on the high end, but do pinch & nose up/down test to make sure that you do not overdo it.

I assume that you are breaking it in with an 11x6 prop right?

And yeah it's a stump puller.

A great value for the money.

Remember it will take over a gallon of fuel before it starts to settle in properly.