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Tuning The Carb After Changing The Choke Cable?


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#1 NunoTT

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Posted 23 August 2018 - 11:56 AM

Ok, so I just changed the choke cable on the Mini and it's runnig weird (well, diferente than before).

 

When I pull the choke cable the engine doesn't rise the RPM's as much as it used to. Also, there is a strong smell of petrol in the air, some popping from the exhaust and some smoke.

 

I take it the carb needs to be tuned, as from the strong smell of petrol the mixture is too rich?

 

I never tuned a carb, so any advice is highly appreciated!

 

Also, from a research on-line the carb is an HS 4

 

Thanks in advance!



#2 SolarB

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Posted 23 August 2018 - 12:04 PM

The carb. shouldn't require re-tuning. Have you checked that the choke is fully closed when the cable is pushed in on the dashboard?

Symptoms sound like the choke is still on.



#3 WillCarter

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Posted 23 August 2018 - 12:17 PM

Make sure there's a little bit of slack in the choke cable and that the choke opens and closes fully

Edited by WillCarter, 23 August 2018 - 12:18 PM.


#4 NunoTT

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Posted 23 August 2018 - 12:19 PM

The carb. shouldn't require re-tuning. Have you checked that the choke is fully closed when the cable is pushed in on the dashboard?

Symptoms sound like the choke is still on.

 

 Yes I have. And even when I pull the choque the car sounds really weird. I pull it and it almost sounds like it's "fighting" to keep running... This is really hard to describe...



#5 WillCarter

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Posted 23 August 2018 - 12:21 PM

Manually move the choke from the engine bay and see if it still sounds weird

#6 NunoTT

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Posted 23 August 2018 - 12:22 PM

Make sure there's a little bit of slack in the choke cable and that the choke opens and closes fully

 

So if I have the choke cable too tight I might be "over choking"? It might be it... At least it makes sense. Didn't really think of that..



#7 richmondclassicsnorthwales

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Posted 23 August 2018 - 12:23 PM

I think you may have pulled the choke lever on slightly when fitting the cable.

 

Go back and slacken off the the nipple which goes through the cable and carb choke lever. Make sure the lever is fully off, then re-tighten the nipple

 

It can be very easy to pull the choke on when fitting the new cable without realising. This should sort your problem hopefully



#8 NunoTT

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Posted 23 August 2018 - 02:42 PM

Manually move the choke from the engine bay and see if it still sounds weird

 

Yep. It still does...

 

I think you may have pulled the choke lever on slightly when fitting the cable.

 

Go back and slacken off the the nipple which goes through the cable and carb choke lever. Make sure the lever is fully off, then re-tighten the nipple

 

It can be very easy to pull the choke on when fitting the new cable without realising. This should sort your problem hopefully

 

I did that and I even moved the choke manually like WillCarter said and still does the same weird thing..



#9 WillCarter

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Posted 23 August 2018 - 02:43 PM

You didn't do anything with the throttle cable did you? 



#10 richmondclassicsnorthwales

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Posted 23 August 2018 - 03:26 PM

Have a look at the jet, and see if the jet is stuck open. The jet could have stuck down / open if it has been opened fully with fitting the cable to the throttle linkage.  Hope you know what I mean by the above illustration.

 

Also have a look and make sure the small linkage to the jet is fitted, and has not been dislodged while fitting the new cable. The jet could drop on its own then, and give a "chokes on" scenario

 

It has to be something daft, it really does, after all, you have only fitted a new cable. Something is not attached or stuck



#11 NunoTT

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Posted 23 August 2018 - 03:42 PM

You didn't do anything with the throttle cable did you? 

 

No I didn't. I really only changed the choke cable

 

Have a look at the jet, and see if the jet is stuck open. The jet could have stuck down / open if it has been opened fully with fitting the cable to the throttle linkage.  Hope you know what I mean by the above illustration.

 

Also have a look and make sure the small linkage to the jet is fitted, and has not been dislodged while fitting the new cable. The jet could drop on its own then, and give a "chokes on" scenario

 

It has to be something daft, it really does, after all, you have only fitted a new cable. Something is not attached or stuck

 

I think I know what you mean, but how do I check it? Do I need to take the carb apart?

 

I'll have a friend come over tommorow to help me with the carb. After all, a second pair of eyes can help. He might see something I don't...

 

Also, if I clean the spark plugs, will they turn dark after just one or two minutes of runnig if the mixture is too rich or the jet is stuck open? 



#12 richmondclassicsnorthwales

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Posted 23 August 2018 - 06:09 PM

You don,t need to take the carb apart, you would be able to see the jet from above and move your head to the radiator side looking at the base of the carb

 

The plugs would soot up a bit if the choke is active, so best cleaning after you have sorted your little problem.

 

Make sure too you have not pulled a lead off slightly from the top of a spark plug giving it just a 3 cylinder running scenario. Take each one off and replace them firmly on each plug

 

It will be some thing silly causing this



#13 NunoTT

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Posted 23 August 2018 - 07:59 PM

You don,t need to take the carb apart, you would be able to see the jet from above and move your head to the radiator side looking at the base of the carb

 

The plugs would soot up a bit if the choke is active, so best cleaning after you have sorted your little problem.

 

Make sure too you have not pulled a lead off slightly from the top of a spark plug giving it just a 3 cylinder running scenario. Take each one off and replace them firmly on each plug

 

It will be some thing silly causing this

 

I will do all that tommorow and keep you updated.

 

And sadly, in this Mini it's always something silly and stupid that causes 98% of all my problems...



#14 NunoTT

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Posted 23 August 2018 - 08:01 PM

 


Edited by NunoTT, 23 August 2018 - 08:02 PM.





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