light yellow color on plugs

[Macattack]

What would cause a light yellow color on both spark plugs? I was riding this past weekend and was only able to find a small hill climb that wasn't all torn up and loaded with stumps. Checked my plugs under WOT and both had a light yellow color around the insulator and half way up the ground strap. I'm a bit rich on the bottom end and about perfect in the mid range ... WOT threw me a curve ball. I'm running about 4 gallons of 114 to 6 gallons of 92. I didn't run another test ... no one knew what to make of it. Possible lead foul?

thanks!

 

[NoSecondChances]

What would cause a light yellow color on both spark plugs? I was riding this past weekend and was only able to find a small hill climb that wasn't all torn up and loaded with stumps. Checked my plugs under WOT and both had a light yellow color around the insulator and half way up the ground strap. I'm a bit rich on the bottom end and about perfect in the mid range ... WOT threw me a curve ball. I'm running about 4 gallons of 114 to 6 gallons of 92. I didn't run another test ... no one knew what to make of it. Possible lead foul?

thanks!

Could be, or just the type of fuel that you're running. I know that Av gas we get here makes our plugs white, looks like they are super lean, but in reality it is just right. What about your wash? Look ok? IMO I'd go by the wash more than the plugs if you are running race fuel.

 

[Blokhead]

They would only be "lead fouled" if they quit working.

 

[zebiraross]

Yellow is lead build up. Sometimes it's hard to tell the yellow color lead gives from a greenish yellow that is antifreeze.

 

[Macattack]

Yellow is lead build up. Sometimes it's hard to tell the yellow color lead gives from a greenish yellow that is antifreeze.

Oh, don't go there! I haven't checked the wash yet. I'm thinking just as NoSecondChances said, type of fuel. Retest and find out. Thanks for the info!

 

[whittaker727]

I got that I mine too. I'm running Sunoco 112 w/AC oil. Coolant level and motor temps are good so I don't think it was anti freeze. My wash is great too. I checked mine at the end of a long road pull, I'll try it on the hill this weekend.

 

[irondave86]

mine did the same thing this year, im runing trick 114 with a\c oil? i was wondering what it was too?

 

[jim]

I'm running 100LL...I get a yellow to rust color...must be the lead according to what I'm reading.

http://www.euromotoelectrics.com/BoschSPFaces.pdf

 

[H20SKE]

You should be looking for a thin black line (about the thickness of a fingernail) on the ground. That is where your fuel /temp is talking to you of how rich/ lean it is running. Fuels and oils will change the color of the plug, but the line will always be there. If you are headed down past the half way point of the curve of ground electrode, you are to lean.

H20SKE...