28 replies to this topic

[007xico]

Tok the car to KIWK FIT for MOT and failed for 2 things:

 

1st - brake lights not red enough but i got a pair of red bulbs , so sorted.

2nd -exhaust emissions carbon monoxide content excessive.

 

They told me , must be the carb but can't do anything there , have to get it sorted somewhere else.

Problem where i live there isn't mini specialists , found one in Littlehampton but they weren't there today ( don't know how good they are).

 

I do have a new carb and cone filter to be fitted , any advice would be welcome.

 

Attached pics of the emissions and carb.

 

Many thanks.

Attached Files

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[matty...]

That's running very rich!

Try checking the idle mixture screw, generally they should be screwed right in then backed off 2 and a half turns as a base point.

The float could be sticking, or incorrectly set, causing the carb to flood and run rich also.

Another thing to check is ignition timing, having this too retarded will cause it to run slightly rich too.

[1984mini25]

Fitting your new carb won't solve the problem, as you would still need to have the co set up on the emission tester. The fact kwik fit are saying they can't do just goes to show how little they now about adjusting a carb, its not that difficult while the cars being testing to screw the nut in a few flats to pass. Although that reading is pretty high, apart from screwing in the jet a few turns, I'd also be looking to see if the choke mechanism isn't sticking.

Edited by 1984mini25, 30 October 2015 - 07:23 PM.

[Guess-Works.com]

I have done just that many times... while the engines running and plugged into the sniffer at the MOT, just leaned off the mixture, remembering how many flats or turns so it can be put back afterwards....

[1984mini25]

I have done just that many times... while the engines running and plugged into the sniffer at the MOT, just leaned off the mixture, remembering how many flats or turns so it can be put back afterwards....

 

Although it does depend upon how mini and classic friendly the mot tester is, generally kwik fit and fast fit "garages" aren't.

Edited by 1984mini25, 30 October 2015 - 07:23 PM.

[carbon]

007xico - other point worth checking is the condition of the needle in your HS4 carb.

 

Take dashpot off and check the needle for a wear ridge about 3mm from the face of the piston. If it's worn then first replace with new needle before setting mixture.

 

To get lower CO reading first get the engine fully warm, at least a 5 mile run. On the HS4 there is a lifting pin on underside of piston dashpot chamber.

 

When engine is idling use this lifting pin to raise piston a couple of mm, if the engine speed rises the mixture is too rich, you then weaken off by adjusting main jet up using brass nut, about a flat at a time and repeating lift pin test.

 

For MOT you set it so the engine speed drops (but not stall) when using lifting pin.

[finch661]

my mini runs happy with the co at about 6%. i turn it back before the mot and set it back after

[sonikk4]

Plugs clean and gapped correctly, air filter clean?? double check for any air leaks between the carb and manifold. If thats all good then adjust the mixture screw to weaken the mixture. Oh and as mentioned do a quick check of the timing.

 

If none of this works then its possible the needle may be bent. 

[Cooperman]

First mistake was going to QuikS**t  . Is the Lone Ranger still working there??

 

Now, there was a document issued to MoT Test Stations many years ago about testing cars with SU carbs. The advice was to lean off the mixture and increase the tick-over revs to around 1200.

[blackbelt1990]

Tok the car to KIWK FIT for MOT and failed for 2 things:
 

There's your problem...

[Dusky]

Hmm, always thought you should set the co at the magic number 3.5%? 

 

cheers

[007xico]

Thanks for all the input .

 

Lesson learned NO KIWKFIT.

 

Found what to seems a nice garage that has a mechanic that knows about minis.

I shall see if i don't get screwed again.

Edited by 007xico, 02 November 2015 - 05:01 PM.

[dyshipfakta]

It's not even just minis su carbs and indeed the a series were fitted to loads of stuff and any seasoned mechanic should know the basics.

[CityEPete]

Kwik fitters are not mechanics are they, I took a car there 'once', it failed on everything they had in stock, failed on tyres within the legal tread depth, took it to my normal place and it passed for two more years.

[Cooperman]

I was told a story a few years ago about them.

A young lady took her Escort in for new tyres. They told her she needed new rear dampers, so she had them fit a pair.

Fast forward about 8 months and her car needed an MoT, but as she was busy her Dad took the car in for her. The phoned him to say that it had failed on, yes, soft rear dampers, so dad said to fit a pair. When he later went to collect the car the bill included the dampers, but dad produced the 8-month old bill and told them it was a warranty claim.

They had the cheek to ask why he hadn't told them that when they said the dampers needed changing (again!). He asked "Why"!