I've flown 60-70 tanks through it in a H9 Pizazz. The combo is great fun. I kinda recall trying the 13-6 and 13-7 some time ago and settling on the 13-7, but as I said it won't hurt to swap again and remember why I think it works better. All in all, it is a great engine.. my first and only four-stroke too! It was easy to set-up & run from the get-go, and very neighbour friendly in comparison to the vast majority of my RC fleet which is heavily populated with wailing high performance 2 strokes.

I just wanted to get an idea of how tired the engine was.

MJD