How Does My Spark Plug Look?

[GeneralKayoss]

So I've run 20 tanks of fuel through my new milling saw, decided to have a look at the plug. 30:1 mix and a fat tune. Looks about like it should to me (rich) but I figured I'd let you guys give me a second (more knowledgeable) opinion.

 

[old guy]

I certainly wouldn't run that any leaner.

 

[GeneralKayoss]

I certainly wouldn't run that any leaner.

I thought I had it set pretty rich. About 11,600 rpm on the top end. I did let it idle for about 30 seconds before I shut it off the last time though - but even the idle is set a tad rich about 2400. I don't know a ton about reading spark plugs other than black = rich, tan =good, white/melting = lean. Kind of confused as to why it's tan on one side and black on the other like that lol.

 

[Sidecarflip]

It's like that because of the combustion flame path in the cylinder. Nothing more and to me, your plug looks a bit on the rich side. Should be dark tan and the electrode lighter. Really, the only reliable way to ascertain actual plug color is to chop the saw immediately after running it and keep the throttle completely closed and then remove and inspect the plug color. Just idling down from running RPM will change the plug's color a lot.

 

[ballisticdoughnut]

I’d say you could get away with leaning it out a touch on the high speed. Having said that, if you’re happy with how it performs just send it as-is.

 

[GeneralKayoss]

It's like that because of the combustion flame path in the cylinder. Nothing more and to me, your plug looks a bit on the rich side. Should be dark tan and the electrode lighter. Really, the only reliable way to ascertain actual plug color is to chop the saw immediately after running it and keep the throttle completely closed and then remove and inspect the plug color. Just idling down from running RPM will change the plug's color a lot.

I figured it had something to do with that, I don't normally see that sort of variance in color on a 4 stroke plug. The next time I mill I'll shut it down as soon as I finish the last cut and give it another look.

I don't have any kids so I try to take care of my saws like sons

 

[Vintage Engine Repairs]

That’s a fairly cold rich combustion, not that that is bad for milling.