Lotus Elan

installing priming pump

PostPost by: mikebailey » Mon May 21, 2018 7:48 pm

My Plus 2 130s requires so much cranking after standing a few days it sometimes flattens the battery. I am thinking of installing a priming pump to get fuel to the carburettors to overcome this.
My question is, is there a neat way to do this? The pump obviously has to be accessible from the boot, so do I just fit a loop of fuel tubing through the rear panel?
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PostPost by: yvesmontreal » Mon May 21, 2018 9:18 pm

Hmmm... are you thinking of an electric priming pump?

There are mechanical pumps available for the Ford block that have a priming lever.

Otherwise substituting an electric pump for the original mechanical pump would solve the problem, and is often done.
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PostPost by: mikebailey » Mon May 21, 2018 9:40 pm

I was hoping to install a hand operated squeeze pump, as has been suggested in the forum.
I appreciate an electric pump would do the trick, but comes with its own problems.
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PostPost by: ericbushby » Mon May 21, 2018 10:00 pm

I don`t see any problems with the cube type electric pump I fitted in the front corner of the spare wheel well.
It is energised by a spring return toggle switch under the dash board.
A few seconds is all it needs to prime the carburettors and you can hear when they are full by the change in sound of the pump.
They are available for about ?12.00 from ebay and it was discussed on here a few weeks ago. Search for ... How does a solid state petrol pump work.... for pictures and comments.
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PostPost by: yvesmontreal » Mon May 21, 2018 11:32 pm

There are various options. There are however two things you can't do:

- use an electric pump in series with the mechanical pump. The pressure from the electric pump will defeat the suction valves in the mechanical pump.
- replace the mechanical pump permanently with a cheap electric pump. It will leave you by the side of the road, on a dark and stormy night, better than anything Lucas ever made. Using one in parallel as a priming aid can't do any harm, though.
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PostPost by: Concrete-crusher » Tue May 22, 2018 5:34 am

Undo hope that's not the case as I have just fitted an inexpensive facet type pump in the boot.

I looked up reviews and they seem to be fit and forget .

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PostPost by: ericbushby » Tue May 22, 2018 8:41 am

Hi Yves,
You say that we cannot fit an electric priming pump in series with the engine pump.
That is what I have done and find it completely satisfactory.
The valves in the electric cube type pump do not cause a significant restriction. I can very easily blow through the pump; almost breath through it.
There is no pressure from the electric pump at any other time except for the few seconds when priming before attempting a start.
There is no electrical hazard as the pump is fed via a double pole spring return toggle switch and is isolated when the engine is running.
I still cannot see where there could be a problem and it works very well.
Eric in Burnley
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PostPost by: yvesmontreal » Tue May 22, 2018 9:58 am

It is not a problem if you are not trying to use both all the time.

On another forum one fellow had tried to use an electric pump to assist the mechanical pump; once the engine is started, the pressure from the electric pump is trying to push fuel through the mechanical pump inlet valve; the mechanical diaphragm is now trying to push fuel with the valve opened, working against the pressure, and eventually resulting in less feed pressure to the carb. Final result was vapor lock.
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PostPost by: Geoffers71 » Tue May 22, 2018 10:12 am

mikebailey wrote:I was hoping to install a hand operated squeeze pump, as has been suggested in the forum.
I appreciate an electric pump would do the trick, but comes with its own problems.


I fitted one of these in the boot of my S2. Worked fine for a few months, but became increasingly stiff to use, finally setting rock hard and so useless. Don't know if this is anything to do with ethenol in modern fuels, but I used one years ago to prime an outboard motor with no problems. Reverted to a cheapo electric pump in series with the mechanical one for priming ONLY and works fine.
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PostPost by: ericbushby » Tue May 22, 2018 11:31 am

Yves, thank you ,that explains my confusion. Mike`s original theme of this posting was installation of a priming pump.
Cheers
Eric
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PostPost by: Elan45 » Wed May 23, 2018 10:58 pm

I too had fitted one of the rubber squeeze primer pumps. It worked fine for a couple of years, but 2 years ago while using the squeeze pump, my hand was suddenly wet and it was determined the rubber bulb had split and failed. My S3SS was fitted from new with bolt-on wheels and coincidently w/ the primer pump failure, I was also plagued with wheel/ hub failure. Back in MarchI finally got another wheel blasted, primed and painted, then had the old Yoko Aoo1 tire stripped off and remounted on the replacement wheel. I was able to torque the new wheel onto the hub and replaced the lug nuts w/ some good used ones and I was able to finnaly drive my Elan w/o that rear hub/ wheel noise a couple of times before we headed back to Ohio.

First project this fall after returning to Florida will be to fit the Facet cube pump in series, just as the rubber bulb had been fitted. It will be activated by a momentary contact (spring loaded) switch that will only function while my hand is on it. Seems so much safer than the rubber bulb. And yes, the rubber did seem harder and stiffer every time I used it over a period of a few years.

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PostPost by: pharriso » Wed May 23, 2018 11:06 pm

With apologies to the original poster this is what I copied:
fuel-bulb-pump1.jpg and


Pump the bulb until it will pump no more... cranking time dramatically reduced :D
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PostPost by: Foxie » Wed May 23, 2018 11:20 pm

yvesmontreal wrote:
<snip>
- replace the mechanical pump permanently with a cheap electric pump. It will leave you by the side of the road, on a dark and stormy night, better than anything Lucas ever made. Using one in parallel as a priming aid can't do any harm, though.

Fitted a Facet "cube" pump about 30 years ago. Same pump still going strong after ~75k miles. Just needed to clean the filter last year. :)
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