Symptoms: blows smokey unignited fuel vapour out of the exhaust. Last time this happened I disconnected the fuel and ran it thorough a cuppla start cycles to lean it right out. That was about 4 tanks of 24 liters of fuel ago. It worked.
My initial diagnosis was that I had been running it on a low setting. I thought maybe it was running too cool and not de coking the combustion chamber. I have never run it one any setting but 100 percent since the last failure.
Best fix ? Move North of the Tropic of Capricorn.
Problem solved. The connector that takes the start up current is not up to the job. Inadequate current gets to the glow plug to start combustion but a credible voltage drop still exists.
Fix: involved breaking out the conductors to a more robust connector lug / bus style system.