Dennis,
I had the same experience. I probably had 20 or more hours on the engine in
tuning and just plain reliability testing on the ground before I flew it.

I found oven cleaner worked well. I just soaked the tips for 30-60 minutes
then took a fine wire brush to them and they worked great after than.

Joe Hull
Redmond/Seattle WA, Cozy-Mazda Rotary 69hrs

>
> I have been running my RX -8 at low power settings while finishing up
> the engine install details.  Recently it ran very rough and changing the
> plugs fixed the problem.  The plugs that produced the rough running
> engine are the RE7A L and RE9BT iridium plugs that are standard with the
> Renessis car.  These plugs have a thin layer of  slightly moist carbon
> on the porcelain.  Any suggestions for cleaning?  Can I use a standard
> air operated blaster like is used on A/C plugs?  I believe these plugs
> cost around $35!  Should I be using the different plugs for the Renessis
> in the A/C?
>
> Ed - Thanks for the engine data from your last flight - I plan on
> running some full power static tests on my A/C later this week.
>
> Dennis H.
>