My euro spec 280SE W116.024 with m110 engine has not been driven in 4-5 days. Today I went to start it but it only cranks.

1. I put a couple gallons of gas in to be sure the fuel gauge wasn't grossly off (showed 1/4 tank)

2. changed the cap and rotor with ones off a running 280.

3. changed plugs for W9DC (just did this about 4-5000 miles ago with NGK equiv.) all but one were black and sooty.

4. couldn't hear fuel pump running so I swapped it out with the other running 280 fuel pump (still couldn't hear it and reused crush washers so fuel was spraying out)

5. checked the fuses, just because.

The last few months my starter has developed a terrible flat spot (it has gotten progressively worse) and it now takes many many turns of the key to get it to catch. Also most recently I have had to pump the accelerator a little bit to get the car to fire.

I am sure there is lots of info on this site, but truthfully, I am exhausted from laying out in the cold ALL day and troubleshooting what I have so far.

Thanks in advance for any suggestions