2 stroke piston appearance

[tom3]

Just curious, wondering what the piston top on a decent running two stroke is supposed to look like. Looking down in my blower and the piston is light brown and dry. I get a small chunk of light colored carbon in the plug gap now and then too. Seems like that piston should be some oily? Should I add some more oil in the mix? I use Stihl oil. Little motor is five or six years old and get used quite bit blowing and sucking/bagging leaves.

 

[Hammermechanicman]

No the piston should not be oily. Coffee colored residue is good but black isn't bad. Just depends how much black buildup. If using Stihl Ultra mix at 50:1 any heavier and if carbons up exhaust screens. You are probably good.

 

[Rivets]

Think about this. I have one spark plug that is light brown after running for 25 hrs. I have another plug that is black after running for 25 hrs. Which engine would you say is running properly?

 

[Hammermechanicman]

The light brown

 

[Rivets]

Same with cylinder appearance. Always taught my students that the spark plug will tell you a lot about what is happening ing the cylinder.

 

[Hammermechanicman]

Same with cylinder appearance. Always taught my students that the spark plug will tell you a lot about what is happening ing the cylinder.

Absolutely

 

[tom3]

Thanks for the info. I guess I was living in the past when two strokes were real oil burners.