Reading spark plugs

[Reel Poor]

As for the requested information. Since Coors asked I went doing a little research for some literature and here is a couple of the best articles I came across. There were others but there is a lot of reference material here.

http://www.4secondsflat.com/Spark_plug_reading.html

http://en.wikipedia.org/wiki/Spark_plug

 

[180shabah]

Re: Reading spark plugs

Thanks RP

 

[bruceb58]

Re: Reading spark plugs

This is a quote from the second article:

"An idling engine will have a different impact on the spark plugs than one running at full throttle. Spark plug readings are only valid for the most recent engine operating conditions and running the engine under different conditions may erase or obscure characteristic marks previously left on the spark plugs. Thus, the most valuable information is gathered by running the engine at high speed and full load, immediately cutting the ignition off and stopping without idling or low speed operation and removing the plugs for reading."

That is how I read my plugs.

 

[Don S]

Re: Reading spark plugs

This is a quote from the second article:

"An idling engine will have a different impact on the spark plugs than one running at full throttle. Spark plug readings are only valid for the most recent engine operating conditions and running the engine under different conditions may erase or obscure characteristic marks previously left on the spark plugs. Thus, the most valuable information is gathered by running the engine at high speed and full load, immediately cutting the ignition off and stopping without idling or low speed operation and removing the plugs for reading."

That is how I read my plugs.

That's a fact.
Making a high speed run and wanting to know how the plugs look won't happen if you spend 10 or 15 minutes to get to the dock at idle/no wake speed.

 

[180shabah]

Re: Reading spark plugs

The link to 4secondsflat, was exactly the kind of info I was looking for. I am ordering his book.

 

[Reel Poor]

Re: Reading spark plugs

This is a quote from the second article:

"An idling engine will have a different impact on the spark plugs than one running at full throttle. Spark plug readings are only valid for the most recent engine operating conditions and running the engine under different conditions may erase or obscure characteristic marks previously left on the spark plugs. Thus, the most valuable information is gathered by running the engine at high speed and full load, immediately cutting the ignition off and stopping without idling or low speed operation and removing the plugs for reading."

That is how I read my plugs.

And this is fine for WOT fuel burn efficiency. Don't forget about the mid range, this is where most people operate their engines and where most of your economy will be lost or gained. WOT plug reading is not conclusive to the overall mixture settings of the Carb. Plugs should be read for all three different ranges (idle, mid range, and WOT) for best performance, engine life, and economy. Then the carb should be tuned accordingly.

 

[Coors]

Re: Reading spark plugs

Thanks, RP.

 

[Bondo]

Re: Reading spark plugs

Ayuh,.......

I Agree,......
Except,........
If I'm doing an Idle Test,...... I'll go trolling for awhile,+ Cut the Key to have a Look at the Plugs.......
If I'm doing a Mid-range Test, or a WOT Test,......
I Don't just cut the Key,.......
I throttle back, wait for the Backwash,...... Then cut the Key........

I'm quite sure that the few Seconds of off the throttle Doesn't change the plugs awhole lot.........