ORIGINAL: sendtorandy
I know the A3 is not the recommended plug for this engine. It is a hot plug, but I am running on the rich side while the engine is new and I run 10% nitro. I do intend on changing to a different plug after I feel the engine is good and broke in. With the original plug the midrange of this engine seemed a little rough when left running there. The transition was fine. The idle was perfect. With the A3 the idle, mid range and transition are perfect.
One question, Randy...
Many beginning R/Cers seem to be fearful/reluctant of changing the setting of the low-speed needle in their engine; thinking it is 'factory set'...
It isn't!
In most engines it is intensionally set too rich!
Not only that, but it is the
more important control your engine has, since it determines the richness of the mixture; the fuel-curve, at 'idle to ~75% throttle' (not only at idle, like many people think).
Did you adjust that "seemingly secondary" control, or did you just leave it there?
The high-speed needle only affects the very top of the range.
With the low-speed needle setting too rich, a hot plug may seem better, because it may ignite the rich mixture that will douse a colder plug... But this is trying to correct one wrong with another...
In fact, don't chuck that original plug just yet... It may still prove to be good...