Thank’s guys – awesome info. As i said i am quite new to the Rotax Max, so it is a gradually unraveling mystery!
My floats are 5.2 grams.
I have thoroughly read that awesome article/guide by John Savage, really helpful.
I actually think my issue is not actually with jetting though, but rather some sort of air leak. I have noticed a bit of play in the throttle cable where it joins the carb cap, and it seems that the previous owner has put a short piece of fuel pipe over the connection and cable tied it in place, maybe to prevent air entering? I don’t know how likely that is, or if an air leak there would affect the mix? I assume it would.
I have checked the rubber between the carb and the reed valves – all good. I have checked every tiny bit of the carb itself, surgically clean!
If the throttle cable was unwound to it’s limit – should the engine still be able to idle? Because right now even with the idle screw turned right in, it doesn’t idle unless i wind the throttle cable up a bit… Is that normal for a well used engine? I don’t think it’s ever been rebuilt – next on my list i think! Especially if i’m going to race it – although they are really lax on stuff like that here!
I’m leaning towards the crankshaft oil seals still….. Is it likely to be these – or am i barking up the wrong tree completely?