91 f250 351 efi hard to start when warm outside

[heifner]

Hey guys my 91 f250 starts perfect first time in the morning if I drive it around and the engine gets to temp and turn it off I have to let it crank for like 10-15 seconds stop turn the key again and it starts perfect or if it's really hot outside and it hasn't been drove all day when I try to start it it does the same thing, but when it's cold outside it never has a problem any ideas on what could be the cause?

 

[5.0Flareside]

is it Slw to crank like turn the engine over or just a delay before it finally fires up?

 

[heifner]

Just a delay before it fires but a long one

 

[Fellro]

My 88 plays the same game. I give it a little throttle and it fires up fine.