Fuel pump snags

jrose · Jan 21, 2022

Hi, I have a 109 that was originally a 2 1/4 Diesel that a previous owner replaced with a 3MB 2 1/4 petrol, it has the mechanical driven fuel Pump on it, I get fuel through the pipework when I operate the lever, but hardly anything when it is driven by the engine, I am going to take it off over the weekend to check it out, are there common problems with these. Is it worth replacing the whole thing as the overhaul kit is just s diaphragm and a couple of valves. Not seeing any other parts of the fuel pump for sale.

Wildefalcon · Jan 21, 2022

Is the lever on the camshaft properly? If the lever pumps by hand, then it's not the diaphragm.

Wildefalcon · Jan 21, 2022

If it's a generic pump, not the original, then you might need a spacer to get the cam to work it.

jrose · Jan 21, 2022

The pump is the original one on the engine, I have never taken it off. I will remove it tomorrow and see if the arm that is driven by the cam is worn or anything looks out of place.

Shippers · Jan 23, 2022

jrose said:
Hi, I have a 109 that was originally a 2 1/4 Diesel that a previous owner replaced with a 3MB 2 1/4 petrol, it has the mechanical driven fuel Pump on it, I get fuel through the pipework when I operate the lever, but hardly anything when it is driven by the engine, I am going to take it off over the weekend to check it out, are there common problems with these. Is it worth replacing the whole thing as the overhaul kit is just s diaphragm and a couple of valves. Not seeing any other parts of the fuel pump for sale.

What was the reason for it not now working?...have you removed it for some reason?...

jrose · Jan 30, 2022

Shippers said:
What was the reason for it not now working?...have you removed it for some reason?...

I haven't removed it, it's still the original one, I can pump it by hand and it does pump fuel, quite stiff to pump until it goes slack, i noticed there isnt a strong petrol smell in the cylinder once I've turned it over and removed the spark plugs, not very wet on the plugs themselves either.

McBoon · Feb 3, 2022

I had problems with fuel and looked at the pump. It too pumped ok manually but not great when driving. I looked at renewing diaphragm but the cost of a new pump was not far off the cost of diaphragm and sundries. Bought new pump, replaced old one, all good now. There was slight wear on the arm driven by cam, but also there was deterioration of the diaphragm (only noticeable once removed)

adrian hogg · Feb 3, 2022

jrose said:
Hi, I have a 109 that was originally a 2 1/4 Diesel that a previous owner replaced with a 3MB 2 1/4 petrol, it has the mechanical driven fuel Pump on it, I get fuel through the pipework when I operate the lever, but hardly anything when it is driven by the engine, I am going to take it off over the weekend to check it out, are there common problems with these. Is it worth replacing the whole thing as the overhaul kit is just s diaphragm and a couple of valves. Not seeing any other parts of the fuel pump for sale.

I think John Richards surplus flogs oem quality pumps for around £25 so hardly worth stripping the failed one

Fuel pump snags

jrose

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Wildefalcon

Well-Known Member

Wildefalcon

Well-Known Member

jrose

Active Member

Shippers

Well-Known Member

jrose

Active Member

McBoon

Active Member

adrian hogg

Well-Known Member

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