Dolmar Spark Plug Question

[Hasufel]

I was cleaning my Dolmar PS-7910 and, when I pulled the plug to see how it was looking, I noticed what looks like some carbon build-up on one side of the ceramic part of the plug. I've put exactly 2 quarts of ethanol-free premix through this baby so far. Aside from being a little hard to start--which I understand is not unusual for Dolmars--the saw ran fine. Do any of you know if the plug's appearance is normal, or is it a sign that I need to do some adjusting? TIA...

 

[Giles]

I was cleaning my Dolmar PS-7910 and, when I pulled the plug to see how it was looking, I noticed what looks like some carbon build-up on one side of the ceramic part of the plug. I've put exactly 2 quarts of ethanol-free premix through this baby so far. Aside from being a little hard to start--which I understand is not unusual for Dolmars--the saw ran fine. Do any of you know if the plug's appearance is normal, or is it a sign that I need to do some adjusting? TIA...
View attachment 183577 View attachment 183578 View attachment 183579

Color of the porcelain should be light tan (coffee with lots of cream) or medium gray. Looks a little lean for my liking.

 

[Hasufel]

Color of the porcelain should be light tan (coffee with lots of cream) or medium gray. Looks a little lean for my liking.

Haha, thanks for the great description. It's hard to tell in the pictures but the dark area is closer to mahogany. I like my coffee with lots of cream and this is definitely darker.

 

[Giles]

Haha, thanks for the great description. It's hard to tell in the pictures but the dark area is closer to mahogany. I like my coffee with lots of cream and this is definitely darker.

I think you will be safe to shoot for that color on the entire porcelain.
It should also start easier. Screwing out the "H" carb screw will richen. You need it to "four stroke" (burble) at wide open throttle, with no load, but clear up when making a cut.

 

[Giles]

I think you will be safe to shoot for that color on the entire porcelain.
It should also start easier. Screwing out the "H" carb screw will richen. You need it to "four stroke" (burble) at wide open throttle, with no load, but clear up when making a cut.

This is the spark plug from one of my saws---

 

[Hasufel]

View attachment 183612

This is the spark plug from one of my saws---View attachment 183612

Yup, that's about what my morning coffee looks like. Definitely not what my plug has on it. Thanks again!

 

[CTYank]

View attachment 183612

This is the spark plug from one of my saws---View attachment 183612

What I can see (focus not too great) looks a bit on the dark side, if it was properly "exercised" prior to pulling the plug. Meaning, more than a few minutes at full-song. When things are about right, with a proper heat range, the insulator should be mostly white to light beige, with a dark stripe down near the base, IME. Holds true for road-racing 4-strokes, too.