Starts perfectly fine when engine is cold but when driven after 30 mins and when engine is hot I have to hold onto ignition for 5 seconds and it cranks and keeps going until it starts

behaves like a cold start on a carburtored car, but this 91 500SL is injected, could it be dirt in the fuel lines or injectors?

Any advise will be helpful

on another note, I notice the SLs have 2 auxiliary fans, I have never seen mine come on, what are they used for? AC?

1991 SL 500 119K miles - the head turner, but sucks to maintain
2005 Acura TL - my reliable one, love the bluetooth
2002 Mitsu Montero
2001 540i - bye bye to a new home