Read my plugs, was carbon fouling on 93 pump gas but not on 96 vp?

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Different fuels burn differently & can leave different colour deposits. Nothing wrong with the plugs, NGK 5 is the correct heat range. Idle or cruise might be a little rich & as others have suggested, you could advance the timing slightly [ 2-5* ].
 
TrailBeast said:
Change of color up towards the tip is late timing, and more towards the threads is too much.
Middle of the bend is about perfect IMO.
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Sorry but this is just myth. People who really know what they are doing can get tan all the way down the porcelain to the boundary layer.
 
Hysteric said:
Sorry but this is just myth. People who really know what they are doing can get tan all the way down the porcelain to the boundary layer.
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Not on US pump gas. You do that and it will kill power. Every single time.

Even on race fuel I don’t get color like that, even though you are going to quote Shrinker (out of context) to try and prove your point.

No one I know puts that kind of color on a plug. No one. They must all be idiots.
 
So should i leave the heat range plug i have in it now and adjust the idle mixture a little leaner? The plugs look white in the photo because of the flash, they are a very light tan/gray in natural light, ill see if i can get some pics of them outside maybe they will show up more true
 
A full heat range may be too much but it would be worth testing if you want to narrow it down to a nats ***. Start with idle tuning and see if it cleans up the soot.
 
TT5.9mag said:
A full heat range may be too much but it would be worth testing if you want to narrow it down to a nats ***. Start with idle tuning and see if it cleans up the soot.
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I will try to cut a couple of the spark plugs to see if i can get you guys more info, 5 of the plugs are a touch black mid way down the porcelain but cylinder 7 and 8 look the same and the porcelain is pretty uniform as deep as i can see
 
Might try taking the covers off the plungers and lightly hold them down to see if you get a different idle quality. If they are bouncing up and down at idle, that is usually not good for a stable idle tune. Spring pressure too high.
 
Rat Bastid said:
Not on US pump gas. You do that and it will kill power. Every single time.

Even on race fuel I don’t get color like that, even though you are going to quote Shrinker (out of context) to try and prove your point.

No one I know puts that kind of color on a plug. No one. They must all be idiots.
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Any fuel will do it. Shrinker was running 21 to 1 comp on pump gas and correlated burn conditions to plug reads.

Who do you know that was doing that? Exactly....nobody..

The reason you claim I miss quote him is simply because you can't understand why he says what he says.

Imagine running 240 psi cylinder pressure on 87 octane fuel.
 
I’m ok with a little bit of color in the porcelain but very little. If I see tan (or any darker than that) I’m taking fuel away from it because I know it’s giving up power.
 
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