The problem was that priming was used. Even an engine that has only run for 40 seconds will have its combustion spaces sufficiently hot enough for no
priming to be necessary.
A taxi to the runway and back, maybe of over one mile, would have got the cylinders extremely hot... Maybe the crankcase and crankshaft and oil would not be up to cruising temperature, but the bits that matter would be very hot indeed (i.e. don't touch!)
I once saw an injected c172 spend about 5 minutes after re-fueling, trying to start a hot engine, there was a good cup full of fuel on the ground under his engine, which fortunately did not catch fire when it eventually started.