Idling too quickly

Engine Oily Bits, Ignition, Fuelling, Cooling, Exhaust, etc.
Post Reply
Message
Author
rdmstewa
Groupie
Groupie
Posts: 98
Joined: Wed Aug 24, 2011 9:45 am

Idling too quickly

#1 Post by rdmstewa » Mon May 08, 2017 3:26 pm

Good afternoon... by heck, he's getting formal!
Haven't posted in ages, managed to fix all the recent issues with the cheque book. Except this one. Had the carbs rebuilt by my local man and now the car runs well, but soots up the plugs in no time. It's also idling at about 1000-1100 rpm. I can't adjust the idle speed because the screw isn't even touching the stop.
Had it down at the local meet the other day and the general opinion was that there was "something wrong" - but we never got to a specific diagnosis.
What worries me is that the choke is fully home and there's a bit of slack in the throttle cable. So maybe the butterflies are in the wrong place. Is that possible? Could I be running on choke all the time and pouring petrol down the bores?
All ideas gratefully received!
Malcolm
Membership no 7477
(Wakefield, Yorks)
'76 2500S Estate

Why settle for a simple solution when a complicated one will suffice?

tony
Senior Member
Senior Member
Posts: 691
Joined: Sun Jun 14, 2009 5:35 am
Location: New Zealand

Re: Idling too quickly

#2 Post by tony » Mon May 08, 2017 7:18 pm

Seems that you have 2 problems, running too rich, wrong needles or out of adjustment. As you say, butterflies misaligned.Suggest that you take it back to your repairer and get him to do a proper job which is what you paid for. :shock:
Tony.
1976 2500 TC.

Lots of bits

1999 BMW Z3.
2003 BMW 525i Touring.
Hopefully not needing too many bits.




.
Hopefully don't need bits !

Dazzer
Groupie
Groupie
Posts: 36
Joined: Sat Dec 27, 2008 10:46 am

Re: Idling too quickly

#3 Post by Dazzer » Mon May 08, 2017 10:06 pm

Yes the butterflies need slackening off and allowed to seat before fastening back up and re checking. You'll need to take the carbs off the car to do it properly.

User avatar
atom
Groupie
Groupie
Posts: 32
Joined: Mon Dec 28, 2015 3:29 am
Location: The Hague, Netherlands

Re: Idling too quickly

#4 Post by atom » Mon May 08, 2017 10:39 pm

I hope that rebuild means new butterflies and axles in this case. Air leakage because of sloppy axles is a very common reason for idling too fast without being able to calm it down.
Onno Zijlstra

2000 Mk2 saloon 1970 - laurel green
Vitesse Mk2 saloon 1969 (under construction) - royal blue
Herald 1200 convertible 1967 with 1300TC engine (under construction) - white

Mike Stevens
Site Admin
Site Admin
Posts: 3364
Joined: Mon May 08, 2006 9:50 pm
Location: South Oxfordshire, UK

Re: Idling too quickly

#5 Post by Mike Stevens » Tue May 09, 2017 9:03 am

Hi Malcolm!

Don't forget that originally, your carbs would have had poppet valves in them. These were supposed to open on overrun but only on overrun. Over time, it seems as if the springs weaken and they can open a bit on tickover. The general cure is to replace them with plain butterflies - or solder the old ones up!

If the carbs have been rebuilt with new (plain) discs, then it sounds like they've not been centralised properly. This is usually done by leaving the fixing screws loose and letting the butteflies 'snap' shut a few times. Then do the screws up!

Mind you, your man should know about all this!

BTW, I've just sent you an email.

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1967 Herald 1200 Convertible rust should be white
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

rdmstewa
Groupie
Groupie
Posts: 98
Joined: Wed Aug 24, 2011 9:45 am

Re: Idling too quickly

#6 Post by rdmstewa » Tue May 09, 2017 12:37 pm

Thanks folks - this is what I rather suspected, and it looks like I'm going to have to sack my man... he's normally very good but he let me down again the other day on something else. Unfortunately, despite understanding everything that's been said it's beyond my capabilities to take the carbs off, mainly due to the fact that my hands aren't what they were - age and all that :(
Time to wield the cheque book again! Nuisance, that, I'm trying to save up to get the rust in the screen surround fixed...
Cheers
Malcolm
Membership no 7477
(Wakefield, Yorks)
'76 2500S Estate

Why settle for a simple solution when a complicated one will suffice?

pete lewis
Groupie
Groupie
Posts: 77
Joined: Fri Aug 01, 2014 2:50 pm
Location: Luton

Re: Idling too quickly

#7 Post by pete lewis » Mon May 15, 2017 1:08 pm

if they have temperature compensators on the side they may be set open when they need to be closed at normal temperatures

held on the side with 2 screws, and sealed to the body with two O rings , the plunger inside needs to be seated closed, adjust by tighten the small nut on the bi metal strip.. its more important they are closed than exactly right. or idle speeds and mixtures cannot be set up.as they bypass air past the throttle plates

but yes check the t plates are fitted the right way round ( yes they are chamfered to seat when closed) and are centred ok

Pete
Pete Lewis
Luton
also area organiser for herts and beds tssc.

Mike Stevens
Site Admin
Site Admin
Posts: 3364
Joined: Mon May 08, 2006 9:50 pm
Location: South Oxfordshire, UK

Re: Idling too quickly

#8 Post by Mike Stevens » Mon May 15, 2017 1:41 pm

Malcolm's is a '76 'S' so should have HS6s. Were these fitted with temperature compensators like the CD range?

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1967 Herald 1200 Convertible rust should be white
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

rdmstewa
Groupie
Groupie
Posts: 98
Joined: Wed Aug 24, 2011 9:45 am

Re: Idling too quickly

#9 Post by rdmstewa » Tue May 16, 2017 8:57 am

Yes it does have HS6 carbs - I got the overhaul kits from Burlen - as I just specified the car then I should have got the right needles, I guess, and I would also have got butterflies with poppet valves. Probably standard spindles as well. I can live with the high idle speed, but I suspect I could be washing the bores with excess fuel, so it'll have to be fixed!
Thanks for all your comments...
Malcolm
Membership no 7477
(Wakefield, Yorks)
'76 2500S Estate

Why settle for a simple solution when a complicated one will suffice?

rdmstewa
Groupie
Groupie
Posts: 98
Joined: Wed Aug 24, 2011 9:45 am

Re: Idling too quickly

#10 Post by rdmstewa » Wed May 17, 2017 3:42 pm

Well... there's a garage not far from me that has a '77 Minivan so I figured they might know about this problem... and I've just got the car back. It's now idling at about 750, going like a rocket and although I haven't checked it (it's chucking it down right now) I'm assured that the idle screws are now touching the cam. I don't know what this wonderful chap actually did, but whatever it was it only took him an hour. Obviously something was out of adjustment. I may well pay this chap another visit!
Cheers
Malcolm
Membership no 7477
(Wakefield, Yorks)
'76 2500S Estate

Why settle for a simple solution when a complicated one will suffice?

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest