New to Gas and DLE Engines; I changed the original Un-Marked Spark Plug with a NGK CM-6; I had to use a lot of effort and force to push the metal shielded Spark Plug Boot solidly onto the Spark Plug, is this normal? Also, my engine came with a Spring which I'm presuming goes inside the Spark Plug Boot, does the spring help ground the plug, and is it needed?

Thanks.