No fuel to carbies? - 1969 280S (M130 engine)

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MajorBenz
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Model you own: w108
Region: Victoria
Location: Melbourne

No fuel to carbies? - 1969 280S (M130 engine)

Post by MajorBenz » Thu 15 Feb, 2018 11:58 am

Hello Oz-benzers,

I'm finally getting around to doing some work on "Grace", who has been sitting neglected for about 18 months.
I did some preliminary procedures before trying to start her up - Drained old stale fuel, and refilled / little squirt of oil down cylinders / a bit of hand cranking to loosen things up.
She turns over fine, seems to have enough battery power. When I squirt some "Start ya bastard" down the throttle, it runs for a couple of seconds. But that's it - wont stay started.
I did some investigation of the fuel lines. Syphoned fuel all the way through to the carbies, and there doesn't seem to be a major blockage.
Ran a tube from the pump outlet into a container and turned engine over. Nothing came out. Am I right in thinking this means there is a problem with the pump? Other things that make me think this are: 1.) the fuel line from pump to carbs was bone dry when pulled off 2.) I'm not seeing any fuel coming out the little carb jets when I manually push the throttle arm.

Other pertinent questions:
My fuel filter is before the pump - is that correct? Or should it be after?
Is this mechanical pump the only thing responsible for fuel coming through the system? I don't see anything at the "tank end" in any of the manuals I'm looking at, or on the car itself.

Any advice apreciated.
Cheers,
Dan
Silver 1969 280S - "Grace"

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Bartman4800
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Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by Bartman4800 » Thu 15 Feb, 2018 2:44 pm

Yes,

On a carbie version, it is just the mechanical pump that transfers the fluid.
Your fuel filter is in the correct spot, just before the pump.

Sounds like your fuel pump has either a dried out diaphragm, or the valves are stuck.
Another possibility is that the pump drive pin is stuck. Take off the pump and make sure the pin slides freely and the 90 deg lever moves freely.

These pumps are rebuildable; ask the forum sponsor for a rebuild kit.
If they cannot provide, look on the interweb for Ruddies in Berlin

These pumps are not Mercedes only, they were used on different car brands of the time. Look for brand stamps on the pump.

While you are rebuilding the pump, remove the pre-filter from the bottom of the tank (the big internal hex).
Use a bolt that fits in that internal hex and weld a nut onto it to make your own tool.
If you are close to Perth you could use mine.

If that filter is very dirty, have your tank cleaned. Clean the filter and install with a new O-ring (forum sponsor)

ALSO, and do not forget this: check all your fuel hoses. If dried replace! There are 2 small pieces in the middle of the car near the propshaft. Do not forget these.
Your pump might be sucking air if these are dry and cracked....

Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "daily driver"
2002 VW Passat V6 30V Station Wagon (SOLD - This car into a money pit)
2011 Kia Sportage "Missus commuter Bus"
2002 Mitsubishi Rosa Bus (converting it to a motor home)

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MajorBenz
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Joined: Sun 21 Dec, 2014 7:10 pm
Model you own: w108
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Location: Melbourne

Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by MajorBenz » Sat 17 Feb, 2018 12:10 am

Hi Bart,
Thanks very much for your detailed reply!
Looks like I'm pulling the pump off on the weekend.
Will let you know what I find.
Cheers mate,
Dan
:)
Silver 1969 280S - "Grace"

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MajorBenz
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Joined: Sun 21 Dec, 2014 7:10 pm
Model you own: w108
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Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by MajorBenz » Thu 01 Mar, 2018 2:55 pm

Bartman4800 wrote:
Thu 15 Feb, 2018 2:44 pm

Sounds like your fuel pump has either a dried out diaphragm, or the valves are stuck.
Another possibility is that the pump drive pin is stuck. Take off the pump and make sure the pin slides freely and the 90 deg lever moves freely.

These pumps are rebuildable; ask the forum sponsor for a rebuild kit.
If they cannot provide, look on the interweb for Ruddies in Berlin

These pumps are not Mercedes only, they were used on different car brands of the time. Look for brand stamps on the pump.


Bart
Hi Bartman,

So I pulled the pump, and it looks like I've got a Meyle, fairly similar to those currently for sale on flea-bay at the moment:
small-pump.jpg
diaphragm-small.jpg
It seems more disposable than rebuildable - apart from some bolts that seperate the top half from the bottom, there's no other way into it.The diaphragm is reasonably pliable and no tears. I can't find any replacement diaphragms for this model anyway.

So it looks like my options are buy a similar new replacement, or see if I can source an old used part that's rebuildable.
Any thoughts? Are the older pumps better quality? I know some of them had a manual primer lever which seems like a good idea. Or is it much of a muchness, in which case what are your thoughts on new Meyle v Peirburg v Mercedes ($$$!) parts?

Cheers mate,
Dan
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Silver 1969 280S - "Grace"

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Bartman4800
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Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by Bartman4800 » Thu 01 Mar, 2018 3:56 pm

Cannot tell from that one picture. But usually a Meyle is a throw away pump.

But if there are no tears in the diaphragm, than that is not your problem.
If you put your pump back together, you can test it with your finger.
One port should draw a vacuum, for a prolonged time.
The other port builds up pressure.

Have you checked all your fuel hoses?
Have you checked you fuel pipes?
Have you checked your tank?

Mercedes never built their own pumps, same with carburettors.
I think I have an old style pierburg or a solex, with a lever.

They all do the same thing, but having a priming lever is handy if you don't want to crank for a prolonged time.


Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "daily driver"
2002 VW Passat V6 30V Station Wagon (SOLD - This car into a money pit)
2011 Kia Sportage "Missus commuter Bus"
2002 Mitsubishi Rosa Bus (converting it to a motor home)

User avatar
MajorBenz
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Posts: 49
Joined: Sun 21 Dec, 2014 7:10 pm
Model you own: w108
Region: Victoria
Location: Melbourne

Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by MajorBenz » Thu 22 Mar, 2018 5:12 pm

Bartman4800 wrote:
Thu 01 Mar, 2018 3:56 pm
Cannot tell from that one picture. But usually a Meyle is a throw away pump.

But if there are no tears in the diaphragm, than that is not your problem.
If you put your pump back together, you can test it with your finger.
One port should draw a vacuum, for a prolonged time.
The other port builds up pressure.

Have you checked all your fuel hoses?
Have you checked you fuel pipes?
Have you checked your tank?

Mercedes never built their own pumps, same with carburettors.
I think I have an old style pierburg or a solex, with a lever.

They all do the same thing, but having a priming lever is handy if you don't want to crank for a prolonged time.


Bart
Hi Bart,

So I tested the pump on my bench and it seemed quite functional - moved a half a litre of fuel from one can to another pumping it by hand. I put it back on the engine and put a new fuel filter on to see if that helped. It did. I have fuel getting up to the carbs now - well to one of them at least. The front one seems blocked. When I shine a torch down the carbs and push the throttle can see fuel coming out the jet of the back carb, but the front one nothing happens.

She's close to starting - if I spray some "Hard starter" down the carbs I get ignition, but it can't sustain itself. I'm thinking I'll pull the front carb and give it a clean - maybe rebuild with a kit. Does it sound like I'm on the right track here? The car sat unused for over a year, and I've heard that can block the carbs...

My fuel lines/hoses/tank filter are ok I think. There's no sign of any leaks, no blockages, and it was quite easy to syphon juice through the system up to the carburetor inlets.

Cheers mate,
Dan
Silver 1969 280S - "Grace"

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Bartman4800
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Posts: 1851
Joined: Fri 10 Oct, 2008 12:10 am
Model you own: w111
Location: Perth WA

Re: No fuel to carbies? - 1969 280S (M130 engine)

Post by Bartman4800 » Thu 22 Mar, 2018 5:26 pm

On the front carb, the float needle might be stuck.

Use a large screwdriver, and tap the plastic handle against the carburetor body. With a bit of luck, the float needle will drop.

Buy a can of carburetor cleaner (preferably the foamy stuff) and apply liberally on the inside of the carburetor. You can also squirt something through the fuel intake.
This should help to clean up the lot.
Your engine will blow some smoke on startup, but this should subside soon.

Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "daily driver"
2002 VW Passat V6 30V Station Wagon (SOLD - This car into a money pit)
2011 Kia Sportage "Missus commuter Bus"
2002 Mitsubishi Rosa Bus (converting it to a motor home)

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