That will not necessarily help. Optimax models run their "dirtiest" at IDLE and at WOT.
The engine will run it's cleanest where it gets it's best fuel ECONOMY (normally in the 3500-5000 RPM range). That's a great place to run for the purposes of keeping things cleaned up (especially after extended idles).
That half-mile idle is likely where your carbon is coming from. Bet they look much better after a run as described above.Originally Posted by krindgen