My 1980 300SD is hard to start after it is not used for a few days. I know the problem is that the engine is not getting fuel because sometimes the hand pump must be actuated to get the enging to start. I also noted that it does not pump as much fuel out of the tank as it used to. Once the engine is reved up for a few seconds after it starts, it runs flawlessly.
Does this indicate a fuel pump going bad? If not, what else could it be. I have had fuel filters plugup and they did not exhibit these characteristics so I don't think it is caused by the fuel filters.
P E H

P E H
Sounds to me like the supply pump on the side of your injection pump is getting week. This is a cheap easy fix. Good place to start anyway.

There are two valves in the supply pump that could be bad or leaking. If one is bad it would still let you run the car, but after you shut it off, the leaking valve lets the fuel drain from the lines and filter causing considerable cranking if the car has set a while.Try cleaning them,but make sure you put them back in the way they came out. They are identical but face different directions.
You say the previous owner had the same problem.Maybe the valves have been installed upside-down. I have seen this happen quite a few times.Bill Lewallen Lex.Ky.

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Wm.Lewallen: I didn't say anything about a previous owner. I have owned the car 10 years and 110k miles and I never had this problem before, it just started doing it lately so I doubt if the valves are in wrong.
I will try checking the valves as you suggested but how do I do this? Is there a diaphram in the pump that might be leaking and can that it replaced? Are these valves or diaphram available as repair parts or do I have to replace the entire pump?
P E H