Cranking Engine For Fuel Supply

[William2]

My car has a refurbished (new diaphragm) standard fuel pump and Dellorto carbs. I find that if the car has been sitting in the garage for say 2 weeks that I have to crank the engine over quite a lot before the engine starts. Is that normal, as someone I was talking to who was also an Elan owner said that I should check the one-way valve in the fuel pump as maybe fuel is draining back to the tank. I wasn't aware that the pumps contained a valve for this purpose?? My car also has a high torque starter motor if that is at all relevant. Once started she runs like a watch.

[pharriso]

Common issue, the fuel pump is essentially 2 one way valves.... Many of us have installed a "Primer" squeeze pump in the trunk to fill the carb bowls before cranking...

[dougal9887]

I also had this problem, plus a misfire above 6k rpm. An electric pump sorted both.
I used the HUCO low pressure pump and a mk1 Golf fuel pump control switch. This switch powers the pump when it senses ignition pulses but also allows the pump to run for a few seconds when the ignition is switched on, so priming the carbs.
If the car has been sitting for a few weeks I may turn on the ignition twice for priming. You can hear when priming has filled the carbs as the pump stops.

Dougal.

[Chancer]

Those relays are a very good safety measure in the event of a serious crash, I had not thought of their advantages for priming a carburetted engine.

The Ford XR3i also had one that worked in the same way.

[Grizzly]

I had exactly the same problem so i replaced the two one way valves and it starts from cold with very little cranking now.

In my opinion replace the two valves before adding any electric pumps etc, they can be a bit of a pain to get out but it's a straight forward job to do and they make a huge difference when working correctly.

If you do a search there are a few threads about the subject but in a nut shell.... The two valves are staked in position which is why most people leave them but can be removed by carefully removing the the stake holding them in position with a hobby knife (the Alloy is quite soft so easy enough) the then using long nose pliers and a bit of force/wiggling pull the old valve out (you have to destroy it to get it out). Fit the new Valve remembering to clean the recess well and fit the paper gaskets, then use a dot punch to restake into position. Easy

You will find the valves are quite a good fit, i found a piece of Copper pipe fit nicely around the very edge of the valve without touching the mechanism and i was able to tap it gently fully home. Be careful using a socket to tap them home as they are quite soft so have a habit of deforming and therefore not sealing 100% (which kinda defeated the object)

[William2]

Looking at the glass fuel bowl on the pump it is about half full. Does that mean that the non return valves in the pump are working ok?

[tvacc]

Hi guys.
I am having the same issue with the S2 I just bought. I have never had this issue with any other Elan I have had and all of those had the jack shaft actuated fuel pump.

Where are these valves? I have taken apart many Elans, Changed many fuel pumps and I don't recall ever seeing valves.

I don't want to put in an electric as when a young lady pulled in front of my Elan Sprint back in 1986, and I ended up with a totaled front end, the electric fuel pump was still pumping gas on to the motor while I was stuck in the car,

What about putting in one of the new mechanical fuel pumps.....I don't recall seeing valves in those.

I am confused.

Tony v

[tvacc]

Another note. I was going to start looking at this on the weekend. I thought maybe the fuel line is crushed or plugged. Someone installed a primer "press the rubber thing" by the tank. but I don't see that doing much good. I was going to run another line.

Tony

[pharriso]

Where are these valves? I have taken apart many Elans, Changed many fuel pumps and I don't recall ever seeing valves.

I am confused.

Tony v

Tony the 2 circular objects top right in this picture are one way valves...

They are (obviously) internal to the AC fuel pump...

[tvacc]

Ok, but my obvious question is the other Elans I have had never have had this problem.
Why does this Elan S2 have this issue?

Would a new fuel pump fix it?

Tony

[pharriso]

Tony, any elan with the AC pump can have this issue, including my Sprint.

>>Would a new fuel pump fix it?

There are 2 issues that cause long crank time, evaporation of fuel in the carb bowls & back draining of the fuel lines. A new fuel pump would solve the latter only...

[Chancer]

A float bowl cannot be emptied by draining back of the fuel lines, its a physical impossibility.

Evaporation yes, in that case restarting problems will be compounded by air in the fuel lines caused by draining back.

[pharriso]

A float bowl cannot be emptied by draining back of the fuel lines, its a physical impossibility.

I edited my post to say what I meant!

[Chancer]

Dont worry, when I re-read it carefully I was sure that you didnt in fact mean to say the float bowl draining back!

[William2]

Can anyone confirm my previous question that if the glass fuel pump bowl is half full would that suggest that the valves in my pump are working ok??