Trouble starting

[Wallace]

Car is being a riiight ******* to get it started from cold

I have to crank it over and over and over again and again, and it'll just claw its way to idle!
Won't start with choke out at all, and it'll fire up but as soon as I give the throttle a blip it struggles and will mostly cut out.

I've covered

*fuel from fuel pipe to carb - all good
*Replaced the plugs and leads (as a matter of course, used since running in!)
*cleaned the accelerator pump jet (it kinda sprays/dribbles fuel into the carb-which I'm sure is correct??)

Car drives spot on, and will start with no issue if I've used it for a run to the shops or something, it's just purely from cold after not being used for a while

Help

[Wallace]

Just to add,

also checked connections to the Aei unit too?! And all the breather pipes seem ok!

[Tony Walker]

Idle mixture lean. Air leak.

[casper]

Needle valve.Insufficient fuel in the bowl??

[Wallace]

It does idle fine once going--and AFR's are good too, so I assume that that's not the problem? (Please correct me though if I'm missing something)

As for air leak, I haven't sprayed around the carb to check so will do that - where else should I start looking for further possible leaks?

And the carb bowl was full when I took the top off to clean the accelerator pump jet, so I assume I can rule that out?

It's just purely from cold, all else seems sweet as a nut

[Tony Walker]

Just try richening the mixture up. easy to do. count how many turns you do it and if you don't like it... turn it back.

[Tony Walker]

To add... mine idles fine with afrs of 14.9/15.2ish which is pretty lean.

[Tony Walker]

I have no choke and have to pump the throttle about two to 3 times to start it.

[casper]

Has it always been like this?Mine was a pig until i found how she likes it.Mines full choke 3 pumps and she starts first time.

[Tony Walker]

Has it always been like this?Mine was a pig until i found how she likes it.Mines full choke 3 pumps and she starts first time.

lol there all pigs till you find out how they like it

[Wallace]

lol there all pigs till you find out how they like it

[Wallace]

No it's not always been like it.

I gave the carb a full rebuild and refurb after the Noble RR, everything was fine after the rebuild, its only recently that ive had problems- and I get what you mean about learning what they like I thought I'd sussed it how mine likes it

I use to keep my foot flat on the throttle and it'd start really well!

Now though if I pump the throttle a few times, or keep my foot flat it won't start at all, flooding it I assume although I've not actually taken the plugs out at that point to see if they are wet!

I'll try carb cleaner around the carb etc and see if that highlights anything, I'll also try richening it up, although AFR's on idle have been great at about 13's which seem to suit my engine at about 900rpm

Any other suggestions whilst I'm at it?

[Wallace]

Has it always been like this?Mine was a pig until i found how she likes it.Mines full choke 3 pumps and she starts first time.

Having any choke now just makes it impossible, doesnt 'catch' at all - if that makes sense!

[safehands]

My last 5 was a full choke open then 2 or 3 stamps on the pedal as soon as I turned the key... Gave it 25/30 seconds then take the choke down half way again until 5 or 10 mins in and was perfect

[casper]

Does your choke actually work correctly?Did you set the fast idle when you had the carb off?

[Wallace]

Yes Jon, choke is spot on- new cable and works a treat!

Fast idle?

Can u explain a bit more please mate! - only idle adjustments I have made are with screws on the carb, am I missing something cruical here

[Wallace]

My last 5 was a full choke open then 2 or 3 stamps on the pedal as soon as I turned the key... Gave it 25/30 seconds then take the choke down half way again until 5 or 10 mins in and was perfect

I suppose it 'could' be the characteristics have changed with the carb refurb etc, but I really don't think it is!

As said, it use to start lovely once I'd sussed the correct sequence

[casper]

Here you go mate,may not help but worth a look.Your acc pump jet should squirt not dribble.

[casper]

Check for leaks though mate.That could be why you only get the problem when cold.Things expanding when warm covering the leak up.

[Wallace]

Check for leaks though mate.That could be why you only get the problem when cold.Things expanding when warm covering the leak up.

Got a half day off tmrw to get the snags sorted for Blyton so i'll get on the case with it all........

Cheers Jon

[Thundercat]

Just an idea, you say your idle mixture is around the 13s, try leaning it off, may be your flooding it to much on a cold start

[Wallace]

I'll give it a go John

Ive just ordered a couple of one-way valves from Mike too because im wondering if these could be at fault?

Seem to recall 1 of them didnt block when i blew threw?!

[Wallace]

Leaned it off, changed a one way valve - starts reasonably well, but perhaps with the carb having been stripped etc it could be a case of the starting characteristic have changed we'll see........

Soooo my new problem is:

Idles AFR's straight 10's????

Mixture screw is all the way in and makes no difference regardless of amount of turns!

*mixture screw isn't snapped
*fuel isnt squirting from the accelerator/emulsifier tube on idle
*have checked vacuum pipes I think all are ok
*cleaned the idle jet
*checked for leaks with carb spray

I havent checked the FPR as I don't know what to check for?

Any help again much appreciated!

[casper]

When you look into the carb at idle can you see any fuel?Have you checked the needle valve and float height.Alex i mean fuel from the aux venturi onto the plate.

[Wallace]

When you look into the carb at idle can you see any fuel?Have you checked the needle valve and float height.Alex i mean fuel from the aux venturi onto the plate.

No fuel on idle from the 'long tube' emulsifier/accelerator jet which I assume is what u are describing as when u say 'aux Venturi'

Haven't checked the needle valve or float height, but 100% will as I've had the top off so hopefully something's maybe trapped or something like that anyway.....

Will go and check that now!

[casper]

The acc jet is the brass jet hooked over the side you can see as you look down.I dont mean this.I mean any fuel visible at all on idle?Have you been into the enrichement block?possible diagphram split?

[casper]

Think i miss read your last post,thought you was describing the acc jet and aux venturi as one.

[Wallace]

The acc jet is the brass jet hooked over the side you can see as you look down.I dont mean this.I mean any fuel visible at all on idle?Have you been into the enrichement block?possible diagphram split?

Got ya

The acc jet does nothing until I blip the throttle, then I get a good squirt - and it's a squirt not a mist!

Got the carb top off now, and to my amateur eyes all is normal - fuel in there ready to go as such!

I have no idea about setting the float level - although these parts have been replaced with new.......and are operating/appear just as always - perhaps I'm missing something here?

I'll take the enrichment block off now and will pray I find a split diaphragm

Thanks Jon

[casper]

I know you will have Alex but double check and then check again the idle jet and mixture. Use plenty off carb cleaner and make sure the o rings are in place and sealing correctly.I would have expected to see fuel on the throttle plate for it to be a needle jet/ bowel/enrichement block problem.

[Wallace]

Enrichment block is sound, gaskets are sound

I can't see any abnormalities with fuel anywhere

I've just messed about with idle speed and the mixture screw to try and adjust,and the best I can get is AFR's @ 11.4

Idle mixture screw just does fook all now.........I'm completely at a loss

[Wallace]

I know you will have Alex but double check and then check again the idle jet and mixture. Use plenty off carb cleaner and make sure the o rings are in place and sealing correctly.I would have expected to see fuel on the throttle plate for it to be a needle jet/ bowel/enrichement block problem.

Have done mate, but just as a matter of course I'll do it again

[casper]

Would a dodgy carb base gasket cause this??

[Wallace]

Would a dodgy carb base gasket cause this??

I don't know, will check that now too then I'm calling it a night

Just started it gain after all the above and it's over fueling MASSIVELY now

[casper]

What worse?No reason it should be worse with what you have checked.I take it its smoking bad?Have you chrcked the plugs?Have you been into the dizzy,coil,ht leads?

[Brigsy]

Whats your idle set at? Have you got the bullet fitted in the idle jet? Fuel running down carb throat from aux venturi when running?

[Wallace]

What worse?No reason it should be worse with what you have checked.I take it its smoking bad?Have you chrcked the plugs?Have you been into the dizzy,coil,ht leads?

Yeah worse

Smoking good and proper, fuel on the floor the lot

I've called it a night now...........will try and get home at reasonable hour tmrw to start again, and with fresh eyes if you know what I mean

[Wallace]

Whats your idle set at? Have you got the bullet fitted in the idle jet? Fuel running down carb throat from aux venturi when running?

Bullet is fitted yes

No fuel running down unless I blip the throttle, which I believe to be correct?

Idle was set at about 900rpm (just a real steady purrr) and tuned it to get AFR's around 13.6-14.1 which it liked!

But as above, AFR's now flat 10's, has creeped upto 11's messing with the idle........although I'll need to adjust again regardless, it's running like piece of ****e

What's your thoughts?

[casper]

If its that bad and you cant see any fuel on the throttle plate then it must be the spark??Saying that if wjat you have checked made it worse then maybe your on the right track and something has not been put back together right.Idle circuit is really simple.

[Wallace]

Think i miss read your last post,thought you was describing the acc jet and aux venturi as one.

Just opened my eyes too......

I was

Will have a quick read up now....

[casper]

Have you got a spare mixture screw?put a pic up of the one you have.

[Wallace]

I'll go back through the basics again tmrw, to b honest with the night creeping in I started rushing so could of easily caused myself further problems.


Last question of the night

Would a 'faulty' spark cause this kind of an issue?


On idle I'd Expect it, but the car drives fine once past idle and onto part throttle! Even gave it some boost as was fine

[Wallace]

Have you got a spare mixture screw?put a pic up of the one you have.

Got 4 in total, and yeap tried a new one too!

[casper]

I'll go back through the basics again tmrw, to b honest with the night creeping in I started rushing so could of easily caused myself further problems.


Last question of the night

Would a 'faulty' spark cause this kind of an issue?


On idle I'd Expect it, but the car drives fine once past idle and onto part throttle! Even gave it some boost as was fine

I would say yes weak spark could cause unburnt fuel at idle and seam fine when driving.Although saying that your afr should indicate.Sorry mate you need someone who knows more than me for this.

[Wallace]

Jon, you've been a great help thank you

As for the spark, you've written exactly what I think, and it makes complete sense!

Think tmrw, first port of call is to recheck the plugs

Good night

[StuHERTS]

Alex, im home at 2:30,
Mines running fine now,
If you want, try my whole carb in your car to rule yours out?
Let me know geeze.

[Wallace]

Alex, im home at 2:30,
Mines running fine now,
If you want, try my whole carb in your car to rule yours out?
Let me know geeze.

As per msg mate, yes please

[Wallace]

I had a look at the plugs this morning: re-gaped them, double checked the leads.....all fine, and still overfueling.

Will check the dizzy cap tght

The Air Corrector Jet: can this effect things at idle?

Adjusting the float level - is it simple a case of putting another washer in place to 'lower' it?


And ive had a good read through other threads, i'll get Stu to look at the venturi aswell just to 100% rule out the acc pump jet

[Wallace]

Whats your idle set at? Have you got the bullet fitted in the idle jet? Fuel running down carb throat from aux venturi when running?

Forgive my dickhead explanation, but are we talking about the acc pump jet, squirting/leaking fuel into the carb onto the throttle plate.......?

[casper]

Try Stuarts carb,then at least you can rule it out or not.I would imagine your plugs to not look ok with idle afrs of 10.

[casper]

Alex if you can see fuel at idle then something is wrong,it can come from a number of places not just the acc jet.