Sounds like the opposite problem from the 110 thread that is going right now... sounds too rich on the pump. Of course, after leaning the pump, the air bleed for idle will have to be adjusted. In the engines that have the air bleed and the regulator, it is possible to have the pump set too rich, but the air bleed can be adjusted to allow the idle setting to work correctly and the only place the rich setting becomes aparent is in the mid-range. You might want to replace your glow plug first, though. Brand-new engines in the break-in period can foul a glow plug really quick due to the tiny pieces of metal floating around.