Delayed start - a few turns of key to prime fuel - 1985 280SL

[scb71]

I have a new to me 1985 280SL and it often, but not always, has a delayed or hard start. It is like the fuel loses it prime and the lines are empty. Eventually if I floor the gas and keep cranking it will start or better yet if I turn key, not to ignition but to get fuel priming, turn back and then turn on again, then do it again it usually starts right up.

Any ideas? Is there something to check as to why it may be losing pressure? Is there a back flow valve or something?
Also I feel like I may have a slight gasoline smell in the trunk. Nothing major but I do feel like it might be there. I was under the car and didn't notice anything around the fuel pump or fuel filter that indicates and leaking there.

I have never replaced a fuel pump or a fuel filter on a car, I have on my old golf cart and a boat however.... So please keep in mind I am a novice but wiling and capable of learning.