Chances are the engine was running on the lean side due to the crud in the screen. It also could just have been "its time to go"... the engine might have been running lean before its demise and when you cleaned the crap out of the carb screen now running at top RPM and mixture - it lets loose. Sounds like you have a lot of flights on it. Those engines are quite picky mixture-wise.. They run hot as it is, so a lean mixture will spell early death.

I have never run this engine above 7500 RPM. I used an 18x8 prop on my RCS 180.. After about 50 flights, the front bearing siezed and so that was my first and last RCS engine-- nearly lost my CAP on a dead stick. I switched over to a 3W-24 , not a problem since and 100+ flights...

The RCS was a nice engine before the problems though...

DP