Suddenly it commenced spluttering and rising with incredible rapidity, causing a general stampede among our company, who all moved around to the windward side of the geyser.
When fuel no longer covers the longer pipe the engine will lose power/splutter and the rider switches the petcock to the reserve setting, which accesses the shorter pipe.
It started out well enough on the auto choke, but the engine stuttered and spluttered along until the coolant's temperature needle was well into its normal running zone.