Fuel Pumps

I couldn't get my atmo to start even after taking the top of the carb off and removing all the jets and float assy and brass fuel pipe ferals and blowing through again with carb cleaner...but pouring fuel into the carb she fires up straight away...looking at the section dia I'm convinced the float input cut off valve for want of a better word is jamed shut..the ball stuck up..

I'm convinced the float input cut off valve for want of a better word is jammed shut..the ball stuck up..

See pic below about the clip that holds the float from dropping down into the chamber. (click pic to expand)
If the clip is in the incorrect position ..... the engine will not start.
Info is highlighted.

Float Clip.jpg

Also check the solenoid valve (see pic below) which cuts off the fuel unless the engine is being cranked ... or is running.
Unscrew it from the carb .... and the idle jet is pushed into its end ..... remove the jet and clean.

Carb solenoid.jpg

Thanks for the info John, I'll get a chance to look at it again on Friday. Is there a Solex carb spare parts supplier you can recommend, I'm considering replacing the fuel shut off valve (with ball) and the solienoid you showed in your pic...

Is there a Solex carb spare parts supplier you can recommend, I'm considering replacing the fuel shut off valve (with ball) and the solienoid you showed in your pic...

Mike ....... I don't know of one myself, but others on this forum have access to one or more ......... perhaps one of them will respond.
However, the ball valve and the solenoid cut off, incorporating the idle jet, are both cleanable.

[mettersl]

Hi Mike,
John taught me everything I know about these carbs...but here is my slow learners version.

Suggestion one- check the idle jet- its tiny and likely to be the first to block. I don't think you can remove the solenoid that easily- the idle jet mounts on the end of it. Turn on the ignition and check to see if its working by tapping the spade lug connector onto its contact...you will hear a firm click.
Its very easy to unscrew the solenoid and pull it out with the jet attached. The jet should then pull off the end...clean the pin and the jet and make sure the end hole is clear.
If you try to eliminate the solenoid, I don't think there is an easy way to hold the idle jet in place- plus its there for a reason...a hot engine can stay running without ignition.

Second suggestion- is the throttle butterfly opening?...this is a red faced moment from me...last week my Atmo wouldn't start...turned out the jubilee clip holding the water feed pipes was fouling the cold start mechanism and holding the small cab butterfly mainly closed (mostly) so the engine wasn't getting enough air to start.starting. The large carb plays no role in starting a cold engine so just ignore it for now.

Suggestion 3- as John has suggested...the float could be stuck...but if you hold the cold start flap open and peer down whilst opening the throttle the accelerator pump will send a jet of fuel into the engine- if there is none then the float chamber is empty. So the needle valve and float setting needs checking. When I first got mine running the (new) needle valve used to stick and flood the engine (so it wouldn't start).

Suggestion 4 are the front to back pipes clear? On mine the return pipe was blocked - oddly this caused LOW fuel pressure - I think because the pump had no flow, it was producing very little pressure and then regulator wasn't working (that's behind the fuel metering unit). I'd take the feed pipe off the carb and nothing would come out, even though the pipe (and the tell tale clear filter I'd added to check) was full. Crank the car over (can you hear the pump run on for a second or so after the cranking stops) then undo the jubilee clip...there should be a big spurt of fuel, if not check the front to rear pipework. Mine was full of crud and blocked completely on the return side. Once I cleared the blockage, the fuel pressure rose (and one of the joints started leaking as a result..now fixed). Now even a couple of minutes after turn off, if I loosen the fuel supply jubilee there is enough pressure to get fuel out.

Don't worry about the microswitch or sump sensors- they just set the accelerated idle time period- at this time of year they do nothing anyway, and the switches being broken mean that it defaults to the maximum period. Not a tragedy, even if the rest of the system works.

Metering unit...did not work when the car first went back on the road (after 20 years standing) but came to life after a few hours and continues to work.The fuel filter seems to have protected it and it's still working fine, just one joint to it developed a leak after the fuel pressure increase.

Suppliers of spares. Simon autos supply an overhaul kit for both carbs as a kit, including gaskets and needle valves-- its not got some bits in and has too many of other buits but is good value.
In the UK -webcon (ask for Andy Gray) have a carb overhaul kit listed on their website for the smaller carb but have more items if you speak to them, Southern carburettors have some suitable stock for the smaller carb. Drew a blank elsewhere.
Solex france went bust 20 years ago so spares are rare or remanufactured.


Where are you in the UK? There maybe someone locally who might know something (although Atmo experts are as rare as the cars, the same carb set up is also in the 310).

Good luck and have fun
Lee

Hi John and Lee, had a busy day yest at work and my heads spinning a bit ha..your help is very welcome and much apprieated. I'm working away in the week in Dorset and can only get back to work on my car from Friday.. going to print off all your info Lee and sit and carefully read it through today.
I got a reply from carb hospital in Rochester I think saying they stocked a service kit for £40 which he thinks has the fuel input/shut off valve...bit I forgot to say before was the valve - ball I guess was stuck open when we first fired her up and overflowing fuel up the vent tube ...my mech bud was holding his thumb over it to keep her running..that was when the choke was all stuck...both pipes were fully gummed up we latter found out...thanks again

Also meant to say found the super fine plastic filter that's pushed into the back of the main fuel input feral...mines hollow surprisingly...pic to follow..ie a tubular design..unless its broken??

[mettersl]

Hi Mike...
that picture if of the wrong carb...that one doesn't work until the engine has warmed up a bit and you are on wide throttle opening. Thats said...that's the location of the filter, it's just in the other *sible choke) carb. As one feeds the other, I don't think it matters much about the presence of the "last chance" filter in the larger carb as long as it's there in the first one. The hint for me that something was up was some silt in the bottom of the float chamber/
Now I understand, the needle valve...I was talking about the solenoid engine shut off valve sticking out of the side of the first carb ...silly me. It still has the idle jet attached to the end so removing it and cleaning is simple (John C cleaned mine in a hotel car park at Macon). I'd recommend that you do that next as if its blocked it wont idle or run slowly at all.
Yes I had the same problem with sticking needle valve on mine, seems fixed now after some use.
Good luck

Lee

(The single jet carb is also used on some 80s peugeots in a slightly different configuration, but the gaskets, float and needle vale are the same)

Top Tip ........ For any one that has had carburettors flooding and have assumed it had to be the ball / needle valve which is operated by the float .......... never overlook the possibility that it could be the float itself causing the flooding because of a pin hole in it.
This is a common feature with brass floats, Over time fuel enters the float and it starts to sit lower and lower, until it gets to a point where it has insufficient buoyancy in it to control the fuel level in the carb.
As a consequence to this, every time I open my carb up, I remove the float and shake it close to my ear ...... if there is fuel in it, you will hear it sloshing around.
Needless to say, they are repairable.

I'll check that for sure..thanks...
I've hopefully got s service kit for my small carb in the post..fingers x'd
I've been trying to take all the pointers and info yourself and Lee have mentioned.
I wasn't aware the solenoid fuel shut off had a removeable valve in the end...I'm wondering how easy it is to get out + wondering about the small micro plastic filter in the inlet feral that's not shown very well or at all in the tech illustration exp pics...can you remember if its hollow? Or u section..incase the ends come of and stuck in the carb body..just thinking out loud..seems strange design to be hollow..as mine is

Its hollow

????

I wasn't aware the solenoid fuel shut off had a removeable valve in the end...I'm wondering how easy it is to get out

Just to put you in the picture of this solenoid valve.
Once it is unscrewed from the carb, at the end of the brass tube, the Idle Jet is interferrence fitted into its end. Normally you can just grasp it between your finger and thumb and withdraw it from the tube. The only caveat to that is the one I had to remove in the car park in Macon on Lee's Alp. It was seized solid, and required gripping it with a pair of pliers and slowly working it back and forth with larger strokes each time until I could free it. Once that was done the jet was cleared and cleaned with switch cleaner spray through the jet.
I do not anticipate you having this problem as I have never come across it before, but Lee's Alp had not been running properly for many years.
The back of the jet is open and that is where the plunger enters it to blocks off the fuel to the jet when the ign is switched off. This is done to stop pre-ignition once you switch off a very hot engine which would cause the engine to try and run on even with the ign switched off ( also called dieseling ie:- compression ignition )
I hope this helps.

[mettersl]

That’s the part..
you unscrew the brass entry pipe or the smaller, single choke carb, if you are lucky there will be a filter there, In which case pull it out and replace.
The entry pipe fits inside the hollow section and the needle vale is fed from outside (as it he second carb).
Lee

Well good news to report..thanks guys...took solenoid apart and gave it a good clean with contact cleaner..twice for good measure left it soaking while I took top of the 1st carb of..the kit from carb hospital I can def recommend, it has everything right down to new mesh filter, float spring, c-clip for the choke lever the works..plus the important float cut of valve..all back together and fired up first time..did fill the chamber with fuel just to for luck...runs up on choke OK and flap goes to very off posn OK...
But however I adjust the idle screw she dies on me..started at x3 turns out as mentioned by John on prev post...its as if the main carb is not coming in after she's warmed up..read it supplies 20% or was it 10% on tick over...but happy I've got this far...sounds good..just the idle side to sort now...