I want to get this 300d running and on the road. It had been sitting for about 5-7 years when I got it.
I've replaced both fuel filters and the primer pump and the air filter. I've not replaced the old fuel, but I added fresh fuel to it (dumb move, I know).
The car will start right up, and quickly starts "hiccuping" - every few seconds, it cuts out, then comes right back.
If you grab the accelerator and gun the engine, it takes a long time for it to rev up- like a few seconds.
Also, when I pump the primer, it doesn't feel right- like it doesn't feel like it is pumping liquid.
So- I'm guessing that the tank strainer is clogged, and/or I have an air intrusion in the fuel line somewhere.
How hard is it to remove the tank strainer and clean/replace the fuel lines?

There are tons of threads on this forum dealing with air intrusion and clogged strainers.

If you have old fuel hoses, it would be a good idea to replace them. If they've gotten hard while sitting, you can easily have an air leak or a pinhole. Another common leak point on the 61x engines is the primer handle. If it's leaking diesel when you pump it, it's leaking air.

My SDL sat abandoned in a field for 10 years before I resurrected it and put it back on the road. If you haven't done it already, change the engine oil. Consider an additive like marvel mystery oil or something similar to help clean all the gunk and goo out of the engine. It forms in the IP too and can gunk everything up (I have a couple threads on that on this forum).

Do a diesel purge and see if that helps things. If you have varnish or gunk in the IP or injectors, that should get you a long way. Don't bother until you have the fuel hoses replaced and you think the air ingress problem is solved.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

First thing I'd do is apply biocide to the fuel. It'll kill any bacteria and make them small enough to flow through the filter and burn.

5 to 7 years is not that long for a diesel to sit.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yes, you should have drained and discarded the old fuel .

The strainer is dead easy to remove and clean if messy .

You'll need to jack up and safely block the rear end up in the air then use a 46MM socket or large water pump pliers to remove the strainer, clean it well with a toothbrush before re installing, no need to buy the special $40 hose, just peel away the thin sheet metal crimped end, slide off the old dead hose and replace with Diesel rated hose and a proper #13 band typ hose clamp .

Ad some BioBor JF fuel treatment to the new Diesel fuel and try again .

If the primer pump has the white handle, replace it now as it's almost guaranteed to leak air in.....

y hand flex all the various fuel hoses under the hood including the 3Mm return hoses, any that show wetness or cracks need replacing as any air in will cause poor running .

Don't forget th all important valve adjust !most junked Mercedes Diesels were because no one ever did this and tight valves caused hard starting, poor running, stalling and so on .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Don't forget to drain the fuel tank before you take the strainer off. Keep in mind that there will still be some fuel left in the tank so be prepared to catch it otherwise you'll have a big mess.
Another thing after you've taken the strainer off is to put you finger inside tank and see if there's any allege build up. If so it might be a good idea to pull the tank and give it a good pressure wash. Otherwise you'll be trying to pass that crud through the engine. Not good. Also bioside will kill the living allege but the contamination left from the allege will still be there. One byproduct of the allege is acid which can destroy a fuel tank. But if you don't have a bunch of crud on the bottom of the tank then fill with clean diesel along with some bioside and maybe some Howes fuel additive and prime the system and see if there's an improvement.


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Before I'd spend any more time pissing about with it I'd connect a 5 gallon container of clean fuel to the fuel inlet and return lines and start it from that. This will eliminate any question of bad fuel causing the running problem. If it starts and runs fine THEN I'd proceed with tracking down the fuel situation.

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