After testing the electrics at various points it proved that the switch/charge socket does drop the voltage by quite a bit. However I also new that I had flown the model a lot of times and not really worried about how charged the ign battery was...as long as it had some charge it never missed a beat.

Vibration could obviously be a factor bringing down the voltage more or even having intermittent power so the problem was still potentially the switch.

As Tom says though, the problem really does sound like a feed problem. In fact it is reacting exactly as a vehicle my dad owned did a few years ago. It would run fine for a while then choke up and die. Leave it a while and it would be OK again before choking up again.We eventually found that a feed nipple wasn't just a nipple but in fact a long filtered nipple that had what can only be described as a silicon worm inside!!

So, with that in mind the carb on my engine was stripped last night and bingo. The feed filter was cover in a layer of black something! The carb has not been apart before and the model has been flying regularly for over 2 years. The lay up over winter probably allowed the muck to harden forming a major blockage. Result! So, now that I'm 90% sure that is the problem I have left the switch as it looks in good condition but have changed the charge socket for a more standard one.

The onther findings in the 2 flights this year were that at the start of the flights the performance was noticeably better than its ever been! This now leads me to think that the blockage was leaning out the mixture. So, now that I've cleared the blockage I can turn in the top needle and give me more power for the whole flight. The engine was brand new in the model and has done approaching 100 flights so I guess its just starting to run in

Oh and this is the model