Morris Minor Owners Club

literally just discovered these and they do seem a very good idea.

are they worth the money or is it best to rely on ear and experience when adjusting ones carburettor?

Don't waste your money....... No need with an SU carb - lifting the piston tells all.....

thought so, clever idea though

"Lifting piston tells all ....." Please tell more?
Regards .... Peter

There's a small pin on the underside of the carburettor that's used to lift up the piston a fraction of an inch. You want to get it so that when the piston is lifted, the engine momentarily speeds up a little, then returns to normal idle speed.

Although I've got a colourtune (was given one), I tend just to use the plugs as an indicator of the mixture strength.

I have one in a nice black box.
The fact it never leaves its black tells you all you need to know about it.

I actually find an exhaust tester a great way of setting idle mixture.

Idle mixture is easily set 'by ear' - with the lift pin as a check. However - it may bear very little relationship to the overall running mixture, which is checked by inspecting the plugs after a decent run - not after pottering around town.... Colourtune has no sensible use on a car with SU carb(s).

Maybe I should be asking this question under another heading..... Tuning!...... So, I lift the small pin and adjust until more revs appear, then look at the plugs after a longish run and the plugs will look like ??????????? Sorry, I'm a little confused! Not your fault of course, but could you please explain in more detail the best way to tune a carb?
Regards ....... Peter

Engine needs to be hot - so after a bit of a run. Lift the pin slightly and if the engine revs up noticeably, it's too rich - so weaken it slightly and try again. Correct setting is when nothing much happens when you lift the pin...... Plug colours - correct is light beige, too weak is white, and too rich is brown-black.....

Many thanks for that information.
Regards .......... Peter