Well, it turns out the most simple solution is the one that worked. I tried all sorts of things in the beginning and started trying to adjust the low end needle and just made things worse. Then I received a call from Bill, a.k.a. 'the_madgenius' who led me through a series of instructions on how to get this engine performing how it should. Well let me tell you, I followed his instructions and it was actually quite easy to fix.

First I returned the low speed needle to it's original position. Then I closed the high speed needle fully, then opened it 2 and a half turns. I started the engine, opened the throttle up and tried to get it up to full throttle. It was still running quite rough and coughing and spluttering and it took the engine a while to increase in speed. With throttle open completely I then started slowly closing the high speed needle. Immediately I could hear and feel improvement. As I kept closing it gradually, the RPM was increasing and at the same time it was starting to run a lot smoother. Previous to this Bill also explained to me how to listen out for the change between four cycle and two cycle. Eventually I could hear it starting to kick in to two cycle and the improvement was phenomenal. It was actually running normal! No vibration, no more symptoms that I previously mentioned, and it sounded great! Anyway I started to listen out for peak RPM, then went back the other way just a fraction.

What I get now:

The idle is smooth and slow without shaking. It throttles up really well. There's no fluctuation in RPM. And, its very very responsive which feels great!

The only problem I'm having now is the top 1/4 or so of the throttle does nothing. But from idle up to 3/4 throttle it is perfect. After that when I open the throttle fully I don't see any more difference. I'm guessing it just needs a little bit more tuning - that part I couldn't get perfect but I might leave that to the pro's next week. For now the best part for me is that the problems I was having before are gone and it now sounds and feels like a normal engine.

The difference is huge compared to how it was running before. Also the problem I was having when i removed the glow starter is gone. There's no difference when I take it off, it still runs the same.

Thanks Bill you are a legend, I followed your instructions and got the result I wanted.

And also thanks to everyone else here who has helped me, I've learnt heaps from this!!

You guys are great!

Chris.