Hi Chad,
Thanks. yep issue fixed. It was the struggling supplied Lithoim Manganese battery, and it got worse as the weather got colder. A new Lipo 3s pack provided the required punch to start this beast. So now I've gone to a 3s 35c 4000maH pack as the ECU pack.
Engine is really impressive. mate. Absolutely loving it.

Thanks for the quick responses to my emails - both you and Arno.