How do you tune your carbs?

[John Wright]

I am conscious that my carbs need tuning and I was wondering how others went about this. I have some overhaul kits that I want to fit first, but what is the best way to balance the carbs and set the mixture. Years ago I had a TR4 (it also had 1.75 Strombergs)and I used toset themby listening with a small tube to get the balance by adjusting the slow running screws to get the revs right and both carbssounding the same (airfilters off).I set the mixtureby lifting the air valve a small amountin each carb in turn to notice the effect on revs. I used to set the mixture so that the revs rose slightly and then dropped back when the air valve was lifted. I always felt this was a little hit and miss, as there was no real measurement of how close to correct it was. I have seen the colortune, but notice it has been described elsewhere as "average". Does anyone have any experience of success with one? Does anyone have any better way of setting the carbs?

John

[GTJones]

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Hi John

I have also used the method you describe with some success but the best way is to invest in a Gunson Color tune and Air flow meter.

You can set the air flow on each carb (Remove the linkage first) then you can adjust the mixture by fitting the Color tune plug and adjusting the needle until you get a nice Bunsen blue colour shown on the color tune plug.

Both a very easy to use and take a lot of the guess work out of balancing the carbs.

Did mine this way recently and the difference was unbelievable - smooth running and tick over at just 600RPM no searching just a nice even tick over

Gary

[Guest]

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GTJones wrote:

Hi John

I have also used the method you describe with some success but the best way is to invest in a Gunson Color tune and Air flow meter.

You can set the air flow on each carb (Remove the linkage first) then you can adjust the mixture by fitting the Color tune plug and adjusting the needle until you get a nice Bunsen blue colour shown on the color tune plug.

Both a very easy to use and take a lot of the guess work out of balancing the carbs.

Did mine this way recently and the difference was unbelievable - smooth running and tick over at just 600RPM no searching just a nice even tick over
Gary

To use a Colortune you need to know which carb feeds which cylinder, not difficult but another complication, also, invest in a quality balancer, about £45. NOT the Gunsons one. For mixture, you're better off setting the needles flush plus 1/4 turn, then adjust both needles an identical amount - enjoy. Martin.

[GTJones]

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Martin Stevenson wrote:

GTJones wrote:

Hi John

I have also used the method you describe with some success but the best way is to invest in a Gunson Color tune and Air flow meter.

You can set the air flow on each carb (Remove the linkage first) then you can adjust the mixture by fitting the Color tune plug and adjusting the needle until you get a nice Bunsen blue colour shown on the color tune plug.

Both a very easy to use and take a lot of the guess work out of balancing the carbs.

Did mine this way recently and the difference was unbelievable - smooth running and tick over at just 600RPM no searching just a nice even tick over
Gary

To use a Colortune you need to know which carb feeds which cylinder, not difficult but another complication, also, invest in a quality balancer, about £45. NOT the Gunsons one. For mixture, you're better off setting the needles flush plus 1/4 turn, then adjust both needles an identical amount - enjoy. Martin.

Hi Martin

Just use No 7 & 8 easiest to get at and No 8 is passenger side Carb and No 7 is the Drivers side Carb.

Gary

[V Mad]

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John, I have also used the tube method and it works for me, butI now also have a Gunson Carbalancer which also works, and these are very affordable (I was given mine ).

An exhaust gas analyser is probably the best way of setting mixture albeit expensive; also useful if you have a late car that needs to meet emission limits.

I never liked the lift method of tuning Strombergs, it doesnt seem to work.

PS Martin, why the dislike of the Gunson balancer?

[John Wright]

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Thank you all for the advice.

I will invest in a Colortune and a balancer.

John

[Guest]

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Hi Chris, I had one for a while, and it worked OK, but it's flimsy and plastic and fell to bits, parts cracked and broke and I repeatedly had to repair it. Martin.

[Arbman Al]

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Martin Stevenson wrote:

Hi Chris, I had one for a while, and it worked OK, but it's flimsy and plastic and fell to bits, parts cracked and broke and I repeatedly had to repair it.       Martin.

Martin,
You're only supposed to hold it over the air intake on the carb to get a good seal - not hammer it in!:shock::P:P

[V Mad]

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Martin Stevenson wrote:

Hi Chris, I had one for a while, and it worked OK, but it's flimsy and plastic and fell to bits, parts cracked and broke and I repeatedly had to repair it. Martin.

For a minute thereI thought you were referring to your stag Martin

[Guest]

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Arbman Al wrote:

Martin Stevenson wrote:

Hi Chris, I had one for a while, and it worked OK, but it's flimsy and plastic and fell to bits, parts cracked and broke and I repeatedly had to repair it. Martin.

Martin,
You're only supposed to hold it over the air intake on the carb to get a good seal - not hammer it in!:shock::P:P

What's wrong wiv that then - I likes 'ammers ! :dude:

[BlueMK2]

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I have Tony Harts DVD the section on engine tuning is very good, best £17.50 I spent on my Stag.