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2.5 petrol into series III - fuel supply problems


konrad96

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Folks, looking for some help here, hope someone can assist.

I sold my brother my old series III which had a 2.5 petrol from a 90 (already fitted when I bought it). this had been mated to a series 3 Zenith carb and manifold set with the standard exhaust. It always ran okay for me, but was always a little "choked". My brother has just bought (on my recommendation) a second hand Weber DMTL carb and manifolds, hoping to fix the power issue. Now, the inlet manfold from the weber should fit okay onto the series exhaust manifold. My problem comes with all the fuelling gear which is fitted to the 2.5 engine in it's original vehicle - there is a fuel return line, for one thing, back into the tank, and a fuel swirl pot, and I understand that theres also an electric fuel pump.

My question is, can I fit the Weber to his vehicle with the minimum of modifications? Ideally, I'd like to just reconnect his existing fuel line into the new carb, set the thing up and let him crack on. But how important is the fuel pump and the swirl pot, are they essential? Could I get away with one, or the other? Or neither?

for clarity, the way this is set up on a ninety is - fuel pump next to tank, with a separate external fuel filter (like a diesel filter). From this, a fuel line to the swirl pot. A fuel return line comes out of the swirl pot, and back into the tank. From the bottom of the swirl pot, a third line goes straight to the carb.

Grateful for any help. I'd really like to get this sorted out for him.

Richard

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My question is, can I fit the Weber to his vehicle with the minimum of modifications? Ideally, I'd like to just reconnect his existing fuel line into the new carb, set the thing up and let him crack on. But how important is the fuel pump and the swirl pot, are they essential? Could I get away with one, or the other? Or neither?

When I put the 2.5 into my S1 88", I just conected the fuel line to the carb from the SU fuel pump. No return, no swirl pot, nothing else!

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When I put the 2.5 into my S1 88", I just connected the fuel line to the carb from the SU fuel pump. No return, no swirl pot, nothing else!

I'd ditch all the fancy stuff, keep it simple. That fancy stuff is for fuel injection only.

Fuel line to lift pump on engine, and around to crab, via inline filter if you want to. That's it.

Swirl pot, etc, is daft as there is a float chamber full of fuel in the carb, and electric pumps are usually geared to injector cars and are at savage pressure, which can force the fuel out the jet and cause a choke effect.

G.

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The 2.5 petrol in my 109 was installed as Gazzer described above with the none of the extras and it works fine.

that's what I needed to hear - I don't want to fit the carb and plumb everything in and find that the engine runs like a b***h. I'll let you know how I get on...

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that's what I needed to hear - I don't want to fit the carb and plumb everything in and find that the engine runs like a b***h. I'll let you know how I get on...

I'd be interested, as I've heard the Webber isn't as much fun to drive as the zenith, although more economical.

G.

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I'd be interested, as I've heard the Webber isn't as much fun to drive as the zenith, although more economical.

G.

mmm... could be we're talking about a different Weber here. I'm installing the standard fitment Landrover DMTL weber, not the standard replacement for the Zenith. But I do have a question about it: there are three pipe fittings in teh picture. Top one is, I'm pretty sure, for fuel in. Middle one is a vent pipe for getting vapour back into the air intake. But what's the bottom one for? What do I connect it to?

post-13703-1249848641_thumb.jpg

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mmm... could be we're talking about a different Weber here. I'm installing the standard fitment Landrover DMTL weber, not the standard replacement for the Zenith. But I do have a question about it: there are three pipe fittings in teh picture. Top one is, I'm pretty sure, for fuel in. Middle one is a vent pipe for getting vapour back into the air intake. But what's the bottom one for? What do I connect it to?

For clarity, the middle one is the large pipe stub immediately below the solenoid.

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For clarity, the middle one is the large pipe stub immediately below the solenoid.

The middle one vents the float chamber to the atmosphere when the ignition is not live. The bottom is tee'ed into rocker and intake plenum.

post-491-1249856323_thumb.jpg

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  • 3 months later...

Hi chaps, I kow this an old thread, but ive got a question.

I'm putting a 2.5 petrol in my 110, and the lift pump does not seem to engage on the cam lobe. My understanding is that land rover never fitted a mechanical fuel pump to the 2.5 petrol engine. What mechanical pump will fit the 2.5 petrol?

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