Spark plug reading

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danielb927

danielb927

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I'm putting on a new carburetor, so while I was at it, I pulled some of the spark plugs to take a look at how the car was running. What do these say about how the engine was running? I'm not really sure how to "read" a spark plug, I have the guide in the back of the Haynes manual but that's it.

#6 plug, kind of a medium brown color:
p1010988t.jpg

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#2 plug, dark on one side and pinkish-reddish on the other, wet and smelled like gas, obviously too much fuel I guess? I looked, and realized the idle mixture screw was out further on the side of the carb feeding the #2 cylinder so that must have been part of it if not all.
p1010991.jpg

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Should I get new ones or can I use these for anything? They're pretty new, only a few hundred miles on them, maybe a thousand, and they're Bosch Platinums.

Also had the #1 plug out, it looked like 6, but with darker sooty stuff covering most of it and the tan/brown color only on the side of the inner electrode by the grounding strap.
 
from what i was told, the second plug is the way they are supposed to look. like a light toast color
 
I dont know why, but I have never had a good result with Bosch platinums. From what I can see, the choke probably comes off too slow if you have one. It looks rich and sooty. It shows like the hear range is too cold, but I think it's more a function of the plug design.
 
green1 said:
what about the oil on the threads? Internal, or leak from above?
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I'll take a look but I wouldn't be surprised if it was both. I'm planning to change the oil this weekend too since I don't know how much gas probably leaked down while I was trying to start the thing when it wasn't cooperating.
 
340demon said:
heat range looks good timming is a little slow looks like your gas has ethanol in it
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I'm impressed! We do run 10% ethanol here in the middle of corn/soybean country Illinois, timing is about 12 and I'm planning to bump it to 14 initial once I get the new carb on. I've been reading that MSD ignitions don't like platinum plugs? I think I'll probably pick up a set of NGK standard plugs next time I'm at Autozone, run on the current ones and then swap and see if there is a noticeable difference.
 
danielb927 said:
I'm impressed! We do run 10% ethanol here in the middle of corn/soybean country Illinois, timing is about 12 and I'm planning to bump it to 14 initial once I get the new carb on. I've been reading that MSD ignitions don't like platinum plugs? I think I'll probably pick up a set of NGK standard plugs next time I'm at Autozone, run on the current ones and then swap and see if there is a noticeable difference.
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Yeah, i'd run NGKs, they are much easier to read, from what i'm seeing on the #4 pic, looks like that plugs is glazed, so its shot, another thing is the burn pattern on the threads, you want about 3 threads of burn line.
 
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