My 89 420sel will only start after a dozen or so attempts of pouring some gas directly into the carberator. Once it starts it runs fine. I can drive it, park it and restart it same day no problems. Let it sit for a day or two and the process starts all over again. I have located what I believe to be the fuel pumps and fuel filter (one larger cannister and two smaller ones side by side below) there is a plastic cover over all three and next to rear passenger side wheel.

How do I diagnose the problem with limited diagnostic tools? Would it be easier to replace certain items? Finally, I will be working underneath a parked car, Is there a trick to disassembling the filter and pumps w/o getting gas everywhere.

Guys have been great with help in the past. TIA