I just bought a '81 300 sd, 120K miles. This is my first time I work with diesel. It seems to me that I have a problem with fuel delivery. When I turn the ignition key on, I do not hear a fuel pump working. I am under the impression there should be a primary fuel pump in the tank, which suppose to supply fuel for the main fuel injection pump. If this is correct, how can I check the primary fuel pump? Also, what are the most obvious points to check for no start condition? Thanks in advance.
P.S. This is a turbo.

Sounds like you have a long way to go.

There is no electric pump in this vintage of MB Diesel.

Starting problems that happen all at once (not after sitting for months) are typically caused by problems in the glow system, not fuel the fuel system. But that's just a statistic.

If you're unfamiliar with MB Diesels or Diesels in general -- Does the glow light on the dashboard come on for a few seconds when you turn the key to on? Do you wait for the glow light to go out before you turn the key to start?

If you're familiar with Diesels, pull one of the return lines or crack an injector line to see if you're getting fuel to the cylinders.

Try posting in the Diesel forum.

Good luck.

Sixto
91 300SE
87 300SDL
83 300SD ... any takers at $1100? Starts