The idle may be too high. Also check the manual
and make sure you have the correct initial needle
settings. The break-in process can be a little
frustrating. You may even go through a couple of
glow plugs before it's through. Following the
break-in instructions carefully and you will have
a nice running, strong engine.

Just like TowShen said, once the break-in process
is complete you can start tuning for performance.

TRC