MF, choke create suction to suck more fuel through jet (thats how we get the richer mixture to start the motor). Sometimes when you are lucky, you can slam to choke on a few times at full throttle (high speed to give more vacuum) and it will suck through whatever crud is clogging the jet
With regards to pinging, I am fairly sure they add ethanol to 91 octane, giving an octane boost of a few RON
I agree Norm - there were a few servos around here that were dodgy and added it a few years ago; never seen things clog like it.
Tell them its going to run $100 to repair, or its $120 for one of your used mowers (bit better returns)
