Gunson Colortune

[tahoe healey]

I've asked this on another part of this forum (Tools) but it may be specific to Healeys. Has any one had success with the Gunson Colortune on their Healey? I was not successful on my MGB but I've heard some positive on the Healeys.

 

[John Turney]

I have/use two of them. One in cyl 2 and one in cyl 5. I've found they work great. What surprised me was how little I had to turn the mixture screws to go from rich to lean. I've tried the "lift the piston" method and that didn't work for sure.

BTW, after I set the mixture, I used a small drop of green Locktite on the screws to keep them in place.

 

[bob hughes]

I used a single one just to see what was going on with the burn on number 5, as I borrowed it and have a habit of breaking things I borrow from this particular friend ( I think that they must be substandard or purchased from car boot sales), I left it there. As it was the ali end from the long connector came off but it had come off before I borrowed it so I was fairly safe this time.
The result was impressive, I may buy a couple once the engine has been rebuilt.

Bob

 

[Ed_K]

After reading this topic, I searched and found this video about how to use the colortune. Just slide down the screen to find the video...
https://www.ebay.com/itm/Gunson-Colortune...ent&vxp=mtr

I ordered one today after viewing this video.

Ed

 

[TimK]

Tahoe, what do you mean by unsuccessful? What went wrong? I just ordered one and want to know what to watch out for.
Thanks Ed for the link, it was impressive.

 

[BigGreen]

I used one more than 20 years ago on a Triumph Spitfire 1500
It is as simple as shown in the film
Only the light conditions can be of negative influence
In such case use the tube and mirror

Hans

 

[tahoe healey]

It was on an MGB and I had trouble effecting color change using the carb screws. The color I got was blue with yellow center so I never knew if it was too rich or lean. You cannot see well if done outside. I did order another one also so I'll give it another try after watching the video.

 

[Johnny]

I don't know about others, but I've talked to several people who are very knowledgable on adjusting SU carbs and they all tell me their really not necessary. Just follow the manual and you can't be wrong. I figure if they were really that helpful every tool box and boot would have one.
Just my opinion of course.

 

[TimK]

I've gone by the book and have poor gas mileage and the old car bad odor exhaust and a blackened bumper. I'm running rich and can't seem to fix it.

 

[tahoe healey]

I'm hoping it will be less trouble than taking off the carb air filters. I loose skin and drop nuts(from the filters) every time. We shall see.

 

[why]

Johnny seems right on, an SU in good condition will do just what it should as mixture screw turned in, engine RPM drops off and sounds rougher as one carb gets lean, then as screwing it out engine RPM picks up, sound smooths out, and reach point where for about a 1/4-1/2 turn further turning makes no difference where it should be set. Further screwing out makes it overly rich and "blurping" sound starts. Not much more compicated than that. If you S?U does not follow that progression when turning screw, SU needs attention. Ultimate test is pulling plug and examining color, light brown just right, black too rich, whitish too clean. The bit about lifting piston always seemed a bit iffy. When tuning Webers 40 years ago on Alfas, their valves were prone to burning, so would set mixture just a little too rich so the extra unburned gas would cool cumbustion chamber or so mythology had it.

 

[tahoe healey]

I think screwing IN enriches the mixture and OUT leans it as the jet moves up and down to alter the flow. Any way, I was hopping to use it for balancing with out removing the air filters.

 

[John Turney]

I think screwing IN enriches the mixture and OUT leans it as the jet moves up and down to alter the flow. Any way, I was hopping to use it for balancing with out removing the air filters.

Sorry, it's not for balancing; it's to set the mixture. To help get the air cleaners off and on easily, you could go to one of these, which is what I have.

 

[Johnny]

Nice setup, never heard of the company though. Anyway, I just replaced my original Coopers with the simple pancake filters and what a difference it makes. Before, I could never get the car to idle below about 1200rpm, now I can easily go below a thousand down to about 750/800 rpm, and it doesn't hesitate or "buck" at all. I allways felt the original filters were substandard, which there not, but after repainting and adding decals and such I could never bring myself to soak them in gasoline, so I just let them go. Now I know I shouldn't have done that.

Don't get me wrong, if I had a tricarb I'd use the colortune.

 

[nevets]

Johnny
what sort of pancake filters? where are they available?
Thanks!