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Hegg

Fuel Pump and Intertia Switch

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To start, I've got a Federal S1 with twin Strombergs.

Alright, so I replaced my flowlock valve and now fuel pumps up the carbs just as it should. However, it seems to just keep pumping -- so much so that it starts pouring out the breather vents on the carbs. If I pull the little button on top of the grey intertia switch thing, the fuel pump stops pumping.

So the question is, should the intertia switch thing be turning itself off/on so that the fuel pump starts and stops? Or is it leaking out my carbs because my float level is incorrect and/or my float needle isn't seating fully to stop the flow? The carbs are rebuilt and all that, but I'd think that the float should stop fuel flow once the bowl is full. However, I've never had carbs with an electric fuel pump, so I'm not sure how many PSI that thing puts out and if those little float needles are strong enough to stop the flow.

Anyone have any expertise in this matter? Thanks!


2011 Lotus Evora 2+2

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Guest teigan

how severe is the effect you're mentioning. i'm not sure from your tone how much is exaggeration for comedy sake. sounds to me like you need to swap the fuel pump and see if the problem continues. anyway, the inertia switch has nothing to do with it.

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how severe is the effect you're mentioning.
Edited by Hegg

2011 Lotus Evora 2+2

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I don't have the Strombergs on my S1 but had them on the 907 in my 74 Elite. Pump should push fuel and pressureize the lines then stop against the pressure.

As you say, the floats should rise as the bowls fill with fuel and then at the top most setpoint they should engage the needle valve to close off the supply. So check the floats.

The pump will then stop pumping against the pressure.

You might try replacing the pump, especially if you have an older one with points, with a newer solid state pump. I replace mine in the S1 (with Dellortos) with a standard NAPA part pump with a 4 to 6 PSI max. It costs all of about $37 US and resolves the old mechanial points of the original S1 fuel pumps.

The inertia switch has nothing to do with the flow. Mine was removed.

DomG

77 S1 Esprit

USA


Dom Giangrasso

1977 S1 Esprit - Lagoon Blue

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Whe I got my S2 it did the same thing. Replacing the flaot chamber needle valves fixed it. But first, make sure your floats float. Remove the bottom of the float chamber and the float. Drop the float into the chamber so it's resting on the bottom and pour in some gas. The float should live up to its name. If not, replace it. if it does, check it is not set too high. This means taking off the carburettors and turning them upside down and measuring the top of the float relative to the joint face. If that's OK, then go for the new needle valves.

I can't think what would make the pump too powerful. The problem is usually trying to get them to pump at all.


S4 Elan, Elan +2S, Federal-spec, World Championship Edition S2 Esprit #42, S1 Elise, Excel SE

 

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Whe I got my S2 it did the same thing.  Replacing the flaot chamber needle valves fixed it.  But first, make sure your floats float.  Remove the bottom of the float chamber and the float.  Drop the float into the chamber so it's resting on the bottom and pour in some gas.  The float should live up to its name.  If not, replace it.  if it does, check it is not set too high.  This means taking off the carburettors and turning them upside down and measuring the top of the float relative to the joint face.  If that's OK, then go for the new needle valves.

I can't think what would make the pump too powerful.  The problem is usually trying to get them to pump at all.

<{POST_SNAPBACK}>

Thanks for the reply. I couldn't get it to start and run very well after rebuilding the carbs, so I took them back out and raised the float level a bit to see if that was the problem anyway. I just remembered I put them pretty high, so that's probably my problem!

Thanks!


2011 Lotus Evora 2+2

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Hi Hegg

Could be dirt in fuel valve or scoring on the vale seat. Take out valve to look for dirt ,and at the same time you can see if there is any scoring. When you put valve back set the float at the right height and make shore that it is floating and not sticking then you should be ok.

Ray

Edited by Ray

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I got my carbs off and the float setting was a bit low (as in, too much fuel), so I fixed that, but still getting leaks.

I'll take 'em out/off again (ugh) and double-check the needle valves. I'm sure it's something simple.

Anyway, just giving an update.


2011 Lotus Evora 2+2

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Yay, finally got it fixed! It did end up being the float needle having some debris in it which was difficult to remove. While I had the carbs out, I did another thorough cleaning of everything else, and now all works as it should.

Thanks for everyone's input. Now on to the next task...


2011 Lotus Evora 2+2

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