[targa80]

The warm start problem is the loss of fuel pressure in the lines as previously stated by others and the fuel pump has an internal check valve that can fail which allows the fuel line to drain back into the tank. I had this problem many years ago and I did pressure testing of the fuel system. My diagnosis led me to the Fuel pump internal check valve failing, bought the external check valve and fixed the problem (cheap fix). If you decide this is your problem and you buy the external valve make sure you also buy the added hardware to adapt to the original banjo fuel line fitting.