hot spark plug vs cold spark plug

[cookbayou]

Went to oreillys to get a set of plugs for the evinrude and they said they had hot burning plugs and cold burning plugs for my motor. I asked what the difference was and was told one burns hoter and one burns colder. So which is better for an outboard?

 

[tashasdaddy]

Re: hot spark plug vs cold spark plug

GO to NAPA, and get the correct Champion spark plug. or order off iboats marine store.

 

[seahorse5]

Re: hot spark plug vs cold spark plug

Here is the official factory plug chart, use only the one(s) recommended for your particular motor.

http://continuouswave.com/whaler/reference/BRP/SparkPlugChart2008.pdf

 

[F_R]

Re: hot spark plug vs cold spark plug

Hot vs cold relates to the length of the ceramic insulator inside. Heat has further to travel through a long ceramic (hot plug) than a cold plug. Then once it has travelled that route, it is dissipated through the shell to the cylinder head.

That's half the story. The other half is how hot the combustion area is and how fast it can be dissipated from the head to the coolant.

And that is why the plugs have to be matched to the motor. So, you see it is a complicated thing and that's what we pay engineers for.