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Spark plug diagnosis

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Old 05-29-03, 02:43 AM
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Spark plug diagnosis

Hello all,

Just took out the plugs, and they look a little different than usual. They are usually a little fouled. These ones aren't, and I imagine it might have something to do with the fact I just cleaned up the distributor rotor and cap, whose terminals were FILTHY.

Here's a pic....
Old 05-29-03, 02:47 AM
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Timing is maximum 20 degrees BTDC leading and 10 degrees BTDC trailing.

Coolant temps are about 180 degrees F (80 degrees C)

Fuel is regular unleaded (91 octane)

Carburretor is meant to be tuned on the rich side.

Plugs are BR8EQ14.
Fuel filter is pretty new.

Now judging from the charts I've seen, those plugs have been overheating right?
Are the plugs too cold?
Or are the mixtures too lean?
Or some other reason?

Thanks
Old 05-29-03, 04:39 PM
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Looks normal to me from what I can see.
Old 05-29-03, 04:51 PM
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light brown color = rich and good burning?

or is = lean and good burning?

i remember reading about this but i can't find it anymore...
Old 05-29-03, 05:02 PM
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you should be running 87 octane, in a 12a or 13b as long as it is non turbo. plugs look good to me as well.
Old 05-29-03, 06:23 PM
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brown is lean.

black is rich.

plugs should be slightly grey.

it's definately not running rich.
Old 05-29-03, 10:09 PM
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you can't get 87 octane in australia. 91 is the minimum.

the colour is light brown colour, although it is hard to tell from the pics.

Thanks for the responses so far guys. On this forum, and another, no one can agree whether light brown means lean or good. lol
Old 05-30-03, 12:08 AM
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Originally posted by KYPREO
you can't get 87 octane in australia. 91 is the minimum.

the colour is light brown colour, although it is hard to tell from the pics.

Thanks for the responses so far guys. On this forum, and another, no one can agree whether light brown means lean or good. lol
i think drivefast7 is right, i just couldn't remember but it makes sense that it's black when rich and brown when lean...
Old 05-30-03, 01:39 AM
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well I've since been told light brown or grey is fine (NGK website and elsewhere), while orange is lean, and black is rich. Someone's gotta be wrong lol.
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