Starting problem today

[Sept]

I'm going to post this in case anyone has input.

1971 280 SL with SE engine block. This work was done prior to my ownership. 

The car has been running well for several months, it's been driven frequently.

Yesterday the air filter was removed and checked, blown out with compressed air and when I took the air filter housing cover off I noticed the hose clamp connecting the filter housing to the intake wasn't tight. When I replaced the air filter and the housing cover I tightened the clamp on the hose connecting the hose to the air intake.

Today when I started the car it started very roughly, meaning it would start to catch then continue to turn over, sounding like it wasn't getting proper fuel.  After several attempts it started and ran rough for less than a minute and smoothed out.

I drove the car for a short distance, 10 minutes or so and parked it.

Upon re-starting about 2 hours later it didn't repeat the morning start routine but took longer than normal to start.  On the return drive the engine stalled at a stop light but re-started with no problem.  This has not occurred in quite some time.

Returning home I let the car idle a few minutes in the driveway, it's idling around 1,000 RPM which is a bit higher than it has been idling and there seems to be a smell of fuel when the engine was stopped.

My instinct is that the loose clamp on the air intake /cleaner housing hose is unrelated but I thought I would pose the question if somehow the change in the air flow or pressure in the intake was affected.

The rough morning start definitely seemed fuel flow related.

Any thoughts?

[waltklatt]

There is also a smaller 1" or so diameter hose that goes from the intake lid to the idle air mixture screw near the cam cover.
Was that by any chance touched?

[kampala]

Just to confirm the obvious and rule out the impact of tightening the air hose - you may want to run the engine momentarily with the air filter connection as loose as you found it before or removed entirely.   If related to you tightening the clamp, this will tell you.   If it runs okay with a loose or open connection, you most likely have some kind of blockage not allowing air to get to your air filter.

Of course your higher idle is odd if its a lack of air issue. So most likely unrelated.

[Sept]

Thank you, that idea came to me last night also will post a comment if there is any change.

[ja17]

Check that the vacuum line to the distributor is connected.