How do these used spark plugs look?

[Chris B.]

I did some maintenance on some of my OPE and was wondering if you experts can tell how my equipment is running based on how the spark plugs look. These 1st 2 pictures are my Excell Honda powered industrial pressure washer. This was a couple years use but less then 30 hours. I cleaned the plug and reinstalled it and rant it for another 2 years and 30 hours and the 3rd and 4th pictures show those results. The machine seems to be running well overall but sometime hesitates to build pressure when warming up:

The next 2 pictures are from my 1991 vintage Stihl 025 which always runs really good. Odd how one half of the plug doesn't have any carbon built up on it. Not sure how many hours are on this plug but its not much. Used very little:

The new 2 are from my 2014 vintage Walmart Snapper mower with a 8hp B&S engine. Seems to run well with good power for a push mower. Plug has about 28 hours of mow time for the season. I cleaned and reinstalled it:

These last 2 are from my Stihl BG86 blower with only about 5 hours on it for the season. Only takes 10 minutes once a week to blow off my walks and driveway. The unit also seem to run very well and it also 20 years old and starts on the first pull:

Thanks for any input, gentlemen!

 

[spasm3]

Snapper looks like is running rich.

 

[Chris B.]

Snapper looks like is running rich.

I should know this but is that a bad thing? How do I correct this?

 

[mk378]

Look for air filter clogged or choke not opening fully.

 

[Chris B.]

Look for air filter clogged or choke not opening fully.

On which unit? All air filters are clean at all times.

 

[joegreen]

I wouldn’t worry to much about the black plug. Maybe they are using additional fuel to keep the head cooler. But yeah any restrictions in the intake system could cause that.

 

[Lubener]

From looking at the darkened line of the threads on the carbon fouled plugs, the plugs are too cold. A hotter plug would help.

 

[#18FAN]

What oil and ratio is used on the Stihl equipment?

 

[repairman54]

2 stroke plugs looking rich is safer than too lean. As long as performance is fine don't worry. Plugs are cheaper than pistons, lean is mean in 2 strokes.
On the 025 plug position in the cylinder affects the plug color. In 2 stroke racing they index the plugs with the open end of electrode to face the exhaust port for even burn patterns on both sides of the plugs for every last 1/10 of power. Not important or needed in general applications.
Touch of dark coffee brown on the blower plug insulator is perfect safe jetting.

 

[Chris B.]

What oil and ratio is used on the Stihl equipment?

Factory Stihl mix and 91 non-ethanol gas. I just started using the Stihl factory made Motomix fuel this last season.

 

[Chris B.]

From looking at the darkened line of the threads on the carbon fouled plugs, the plugs are too cold. A hotter plug would help.

I'm using factory correct plugs though...