Question as to remove 300td fuel tank or not
 

Recently I bought a 80 300td that had been sitting for a few years. It ran well. The clear filter was black, so I changed it and main filter. Then it began acting fuel starved. I couldn’t fill plastic filter pumping at loft pump. I’ve rebuilt lift pump, new primer, sent out injectors, drained tank and removed filter at bottom. It was black but not clogged greasy or crusty. Bottom of tank has some surface rust but no gunk or rusty scales. I’m not sure if I need to take tank out and clean. What do you think ？

Pulling the tank to clean it or not is your choice.

Personally, I would give StarTron for diesels a try. It has enzymes in it that eat up and reduce that gunk in the tank to particles small enough to pass through filters.

You are going to need to use some sort of treament because the fuel lines from the tank flowered are also 'infected.'

It is entirely possible there is gunk build up in the fuel lines that is partially restricting the lines.

After you get the startron in the tank you are going to need to circulate it through the fuel lines.

Also look up the fuel pressure relief/overflow valve. As they get old the springs compress and at low rpms they don't regulate the fuel supply pressure well.

Ok, how to circulate the Stratton?

From the description, IMO the tank doesn't need to be removed.

I'm in agreement with above. Sounds like tank is ok.

Ok I won’t have to remove it. I have the drained diesel in 5 gallon jugs I plan to add Stratton to them and then put back in car. Sound ok, or throw out

No need to complicate things. Put the startron in your tank and drive.

How old is the diesel fuel in question?

I had some that was sitting 15 years...used it with success. I agree removing tank is not needed.

Car had been sitting for 3 years with about a1/4 tank.

If you looked at the tank screen you must have drained the tank already.

Next is when you change the hand primer you will be circulating the fuel when you use it.

If the car runs safely as was said just drive it. Very little of the fuel that goes into the fuel injection pump goes into the engine. Thel bulk of the fuel goes through the housing cooling the pump and back to the fuel tank.

Maybe try a snake cam
 

Let the fuel get real low. Get a snake cam that has a light on it. Stick it in if you don't mind getting diesel fuel on it and take a look at the tank strainer without having to take it out.

I replaced strainer, had injectors rebuilt by member here, added Kent’s boost pump, now runs great. Added startron

strainer for an '80 300TD?
 

I am facing a possible dirty tank scenario also.
I had algae in the tank when I bought the car 20 years ago and a friend cleaned the tank while I watched. I still have a transfer pump and a 10 gallon plastic tank to store fuel in if necessary. recall the big hex tool needed to remove the strainer I hope I have something to fit.

I am thinking I might have a fuel problem as the 617 turbo transplanted runs well as long as the tank is over about half-full. When it gets low the engine feels more and more sluggish, that's how I describe it because I know I am using more accelerator pedal (from my experienced and calibrated Right foot!)
so I first want to check the strainer.
Now I looked online and nobody lists a strainer for a '79 300TD.

Also, in the back of my mind I wonder if the lift pump might be playing a role in this issue? anyone have experience with that?
DDH

Yes it sounds like a clogged strainer. Before pulling the tank strainer try loosening the tank cap to eliminate a plugged vent causing a suction in the tank and check the fuel supply line for a collapsing rubber hose.