Echo CS590 RPM Problems

[shangwheeler1]

I have an Echo CS 590 Timberwolf. It only had about 15 hours on it and when I was cutting firewood it began revving at a super high RPM. When I checked it out to see what the problem was I found that it lost the chain oiler pump. So I was concerned that metal pieces might've got into the base. Consequently I tore down, cleaned it up and put new seals in. Reassembled it. It still had the rev problem. And inadvertently I had spun the piston backwards so the arrow was pointing towards the rear. Is it critical to have the arrow forward on the piston? Any ideas on what is making it idle so extremely high?

 

[Stihl 99]

Wow that is a head scratcher, carb maybe causing this sounds like.
Yes the arrow direction is critical, that keeps the rings from catching on your exhaust port, wearing grooves in the cylinder, or worse total destruction.
Always have the ring gap to the backside / opposite side of the exhaust port.

 

[shangwheeler1]

Stihl 99
Thanks for the reply. I assumed the arrow direction was for a solid reason just never realized what it was. Now that you have mentioned it, carburetor does sound like a possibility. I never messed with that to make any changes previous to this incident, but could be defective right from the factory.

 

[Calavera]

Vacuum test and check for air leaks. Any time RPM surges, my immediate assumption is too lean. That has saved me a couple times. Better safe than sorry.

You may be able to adjust the carb and get it running normal, but still check for air leaks because the carb may just be compensating to hide the real probelm.