I have one of these engines. It is currently on a 36inch wingspan model that I designed and built myself.

It is a lovely little engine, the model goes like a greased rat. It is reasonably quiet and starts easily.

However..... when it was new I tried hand starting it, for hours over a period of some days. Not a pop! (apart from a very quiet one from the exhaust outlet but no signs of a start )

In desperation I bought an electric starter... woohooo success !

I still use the electric starter to get it going. I use 10% nitro fuel with castor oil as the lubricant.

Just be carefull... it can easily be flooded with too much prime. Take care that it hasn't hydra locked before applying an electric starter.

After the initial run-in period and over several flights it has proved to be a reliable engine and I NOW like it

I have seen comments from others that it needed an electric starter to bring it to life so it wasn't just my engine that was being difficult, others have experienced the same problem.

The light popping sound you refer to sounds as though it might just be the noise from the silencer as the engine is flipped over, as opposed to an actual `pop' as it nearly starts ???

My other engines, including a TT .15 all start easily by hand, but not the 07.

Reg