I just got my 1/8 scale truck by mail opened it up and tested the pull start but it was to hard to pull so i took out the glow plug and to my amaze the pullstart was easy to pull. Then I tightened it again and the pullstart was impossible to pull. Any ideas on how to fix this? The truck is brand new never started it or put nitro in it.

This is completely normal. When you remove the glow plug you take out the compression the engine has. When you tighten it up you get the compression back. A tight compression is a good thing! The older your engine gets the more wear it will get as well, resulting in a loss of compression and power. If the pull start it too hard to pull just loosen up the glow plug a few turns and start the engine from there, then tighten it back down quickly. Make sure to let the engine warm up before running it though! And go easy on the gas when it is warming up.

So I loosen the glow plug enough so I can pull the pull start and then start the engine. Next I tighten it down while its on? Isnt that dangerous.

I've not dangerous. Just don't make it super loose.

Its called...metal pinch...warm it up...hair dryer, heat gun.. to about 200f before you try to start it. It will start much easyer and your motor will last longer. After the first 1/2 gal. it should loosen up.