Damaging Pistons and Cylinders on 660s

[yungman]

No... Many later moel lean running OPE will show a light or whiteish plug and be fine - MS361 for instance..

Plug reading is "interesting" but not definitive.

Thanks
All 3 of mine are medium brown, I guess I am good!!

Thanks

 

[mountainlake]

If you are using Alcohol containing gas, you will need to re-adjust the H screw richer, which means pulling the limiter cap on the 660. The 066 may not have a limiter cap which makes for easy adjustment.

Since Jan 2007 (?) new Stihl OPE has been adjusted at the factory for 10% ethanol.

Cooler wheather makes them a little leaner also. Steve