Actually, LosiRacer is quite correct. It is not that much of a big deal.
The Go motors are very tight when new (and stay tight up to the 1.5 gallon mark as described in my post above).
All you have to do is:

Fit the supplied break in shim (leave in for first 1 - 1.5 gal)
Have a fully charged glow starter
Pre heat motor with powerfull hair dryer or hot air gun. You need to get it very hot ie: near to running temps
Loosen glow plug half a turn to ease the compression
Place motor at BDC so the crank gets a bit of momentum up

The motor will turn over enough to start. If it jams just turm flywheel with screw driver (prising against chassis) and try again.
If it jams a couple of times, make sure you reheat it again to relieve the pinch a little before trying again.
Make sure you tighten the glow plug as soon as engine fires.

There is nothing wrong with the motor. Go's are just very tight when new, which is good as it makes for a long lasting motor if broken in properly.