# Reading spark plug



## LSUh20fowler (Jan 12, 2010)

Need some help reading this plug. Does it look ok or is it running a little lean? Thanks


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## hp488 (Sep 23, 2009)

It might be a little bit, if you look on the left side of the main page there is a listing just for that.


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## rmax (Nov 21, 2009)

looks some what lean, an looks as there may be a little oil burn also


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## NMKawierider (Apr 11, 2009)

It would be nice to know what machine it's out of and how long has it been in. Because I see some white, its either not been in long or its a bit lean even for an efi. But I see some browning on one side and what looks like deposits on the probe arm, this tells me of some oil intrusion possible from the intake side..possibly from oil from crankcase vent from wheelies. Do you need a catchcan? or do you have some warn valve guides....


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## phreebsd (Dec 16, 2004)

http://www.mudinmyblood.net/forum/view.php?pg=sprkplgchrt


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## wood butcher (May 11, 2009)

None of those pic show what a lean plug looks like.


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## phreebsd (Dec 16, 2004)

granted those are for car applications, but the overheated plug is the lean plug.









​*A white colored plug is caused by engine overheating. Failure to repair this engine will result in severe engine damage. Common causes for this are:*
*Incorrect spark plug (too hot heat range).*
*Low octane fuel.*
*Timing is not set properly.*
*Cooling problems, (dirty cylinder fins, no or low water if water cooled, low or no engine oil).*
*Carburetor air/fuel mixture is too lean (too much air).*
*Leaking crankshaft seals, no oil, base or head gasket leaks, or crankcase leaks on two stroke engines.*




















they all show the same general condition - white too hot



​
the one the OP is showing looks fine to me.


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## KMKjr (Jan 9, 2009)

I'd say she's burning some oil by the looks of her.

A white plug is normally lean (or burning coolant too).


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## LSUh20fowler (Jan 12, 2010)

It was a brand new plug ran for about 2 hrs at all different speeds. Under a load in the mud and wide open on the road. It was put in right after I put 2" snorkle and modified my stock exhaust so its a lot less restrictive. This is on an '09 honda 420 with UNI air filter and 28" outlaws (skinnies). If the porcelain indicates oil burn off, might just be excess oil off the newly oiled and installed UNI filter.
Also, today I put on a PC 3 programmer. Havent had a chance to run it for any period of time yet since programmer. Trying to find someone local to help me tune it in just right.


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## greenkitty7 (Jan 26, 2011)

then it probably was burning lean.


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## LSUh20fowler (Jan 12, 2010)

Set up an appointment to be tuned at Hormells next week.


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