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MG TD TF 1500 - Colourotune

Is it correct that colourotune plugs do not work with modern, ethanol based fuels? I have been told they just show yellow all the time.


Jan T
J Targosz

Jan, there are hundreds of positive reviews of the Colortune device. I would guess that the majority of those reviewers had some ethanol in their fuel. When I bought mine I checked the Gunston site to see what they said about ethanol. You guessed it, nothing. I know I have ethanol added gas in my 51 TD and the Colortune showed orange, yellow and blue. Sorry, not a definitive answer but that is my experience.

Tim
TD12524
TD26711
Timothy Burchfield

Seems unlikely to me as alcohol burns with an almost invisible flame, therefore unlikely to contribute any colour at all. The Colourtune is of limited use to us anyway. If it shows yellow on acceleration and blue at steady rpm across most of the rev range, then all is well (probably). If it shows yellow over a wide range of rpm, then a different needle is probably required. Adjusting the jet nut only has a significant effect at idle.
Not many of us are prepared to change the needle without using a rolling road.
Dave H
Dave Hill

Colortunes will work with modern fuels but if your engine is burning any oil whatsoever you'll never really get it to show blue... it will always have some orange.
Kevin McLemore

I put in an AEM air/fuel gauge, mounted inside the glove compartment. It gives a good idea what is happening with the mixture. Initially there was a lot of movement at idle, and I realized the carb pistons were under-damped. I am now a believer in the thicker damping oil school of thought. At speed the GJ needle is right at the theoretical value between 14 and 15, which might be a bit on the lean side.

Jim
J Barry

I have had great luck with the colortune. The engine has to be fully warmed up, with the choke fully off to work. Often I have to bump it off idle to get the true blue flame.
Another trick with duel carbs is to check cylinder 1 and 4 to ensure a consistent mixture.
The correct mixture will always be blue, with yellow streaks popping in.
This is a genius tool. Very simple and gives accurate mixture results. Blue is blue.
Be well,
David.
D. Sander

David, exactly my procedure and results.

Tim
Timothy Burchfield

David, your are absolutely correct that you need to check 1 & 4 to be on-the-money. Indeed, I own two Colourtune plugs... and that's where I put them when I tune. That way I can get it all done in one go.
Kevin McLemore

This thread was discussed between 15/01/2019 and 16/01/2019

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