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Gunson Colortune


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Hi

Unfortunately I cant upload the video - its too big.

Anyway, for those familiar with this gadget it goes where the spark plug goes and then is a Yellow flame indicates a rich mixture, while a Blueish White flame indicates a weaker mixture, usually a Bunson Blue flame is spot on.

So, mine on tick-over was orange. . . yippee thinks as I am having a few issues but as I rev the engine it goes a nice blue...  any ideas?

I am sugaring plug fouling, I am using NGK IRIDIUM IX BPR6EIX SPARK PLUG BPR6E-IX 6637 plugs.  Also the mix coming out of back pipe seems a bit sooty as well.

Thanks

Rich

 

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I have tried to use these with little success. I think modern fuels maybe the problem. They are Ok for a guide but in my experience a much more satisfactory result is to go to a good rolling road and check the mixtures through the Rev range and most importantly when the engine is loaded.

Iain

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Hi Rich,

as you have a US LHD I take it that it is on SU's or Strombergs.

You will not get a good stable flame colour  through the whole rev range.

So a little rich at the bottom end and a little lean at the very top. That will leave 3000rpm nice.

 

I'm sure Bob  ( LeBro ) will chip in as he is quite nifty with the colourtune - he runs 4 at the same time.

 

Roger

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Think the burn colour of modern fuel is different to older formulations. I found when using these that I had to err more on the side of yellow otherwise things were way too rich. Now if use an AFR meter which is much more successful. 

Tim

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Personally not had much success with Colortune on the TR. I usually end up judging whether it is too rich or lean from the way it runs and plug and exhaust colour. I also use the lifting pin on the Strombergs as well to check mixture strength. Not as accurate as a rolling road but ok for general road use. I first used Colortune on a 1967 mini and then it did seem to work well but for some unknown reason on the TR I end up with it reading rich when it is running ok and plugs are light tan in colour. The mini was single SU carb but the TR is twin Stromberg. Maybe Fireman Tom's set up with 4 Colortunes gives a better result.

Keith

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Hello Rich

Here is a link to how to tune Strombergs that mentions the lifting pin to adjust mixture strength. If there is no lifting pin then simply lift the pistons about 1mm with a screwdriver.

https://www.howacarworks.com/fuel-systems/adjusting-a-stromberg-carburettor

This is how I adjust mine on the 4A and it seems to work.

Keith

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I've always found the Colourtune more precise than the lifting pin.

On 5/20/2019 at 9:01 PM, Tim D. said:

 I found when using these that I had to err more on the side of yellow otherwise things were way too rich. 

Tim, have you got that the right way round? Yellow flame indicates a rich mixture.

Pete

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Pete, you are right. I ran it on a yellow flame because otherwise it seemed to be running lean. 

Tim

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