Dave, I was talking to a good friend of mine yesterday about fuel differences between the States and Australia. He's a small engine mechanic (power tools and bikes) with 30 years experience - including dealing with imported products from the USA.
He told me that the fuel here is different from the States in that our fuel tends to be "fatter". That is, "there's more in there that burns" as well as more complex (larger) molecules.
Anyway, the point he was making is that the effect is actually counter-intuitive. He has found, with imported small engines from the States, that they tend to arrive here set too lean for our fuel (we don't really have emission control laws here for power tools so these are stock from the supplier) - and they can run very hot. He speculates that our fuel generates a slower burn, and possibly is more viscous (slowing the flow through the jets).
Whatever the reason behind it, he finds he has to tune engines from the States the same way he would to make an engine run richer, to compensate for the difference in the fuel.
At the end of the day, I'll be tuning for my specific engine, but I found the conversation fascinating - and relevant to this discussion
Dave wrote on 02/22/17 at 03:18:46:I had to go pick up a new motorcycle last night......so I didn't have time to root through the pile. I am pretty sure I got one somewhere.
And our jetting advice might also need a bit of adjustment for your use in Australia.....the fuel that they sell you may be completely different than what we use in the US. Most of our fuel has 10% ethanol blended in, and that requires jets that are just a little bit larger than it would for pure gasoline.