Spark plug Guru's question

What is the difference between NGK (brand?) D7EA and D8EA? Spark, Fuel, Air... so my air is good with new pods.. my fuel is good with clean carbs and gas filter.... so it must be the plugs.. I ordered D8EA as per manual.. I pulled the old plugs out and the previous owner was running D7EA.. anyhow with the new plugs it fires RIIIIIIGGGHHT up!! Just wondering the difference between types of plugs... I googled it and can't find anything... may solve why the previous owner decided to go with D7EA and causing probs

 

The "7" plug was just one "heat range" hotter.

Found by googling "NGK".... The following is a copy and paste from NGK.....

FAQs - Spark Plugs

Q: Why are there different heat ranges?

A: It is a common misconception that spark plugs create heat. They don't. A heat range refers to how much heat a spark plug is capable of removing from the combustion chamber.

Selecting a spark plug with the proper heat range will insure that the tip will maintain a temperature high enough to prevent fouling yet be cool enough to prevent pre-ignition. While there are many things that can cause pre-ignition, selecting a spark plug in the proper heat range will ensure that the spark plug itself is not a hot spot source. More information about heat ranges can be found here.


Here's a link to NGK's plug part number decoder......

http://www.ngksparkplugs.com/docs/tech/ ... berkey.pdf

 

Also remember that NGK's heat range numbering runs opposite of everyone else's (that I'm aware of). The lower the number--7 vs. 8--means a hotter plug.

 

Heat Range Explained and Illustrated:

http://www.ngksparkplugs.com/techinfo/s ... country=US