Club 80-90 Forums

has anyone used gunsons colortune to help tune the air/fuel carb mix on our campers?

successful?

standard 14mm colortune - or long 14mm adapter?

easy / obvious to do? -

any body elses experience welcome -
thinking of avin a go today - black sooty (sorry sweep) spark plugs - equal too rich a mix ?- adjustment required -
plus idle running closer to 1000 as opposed to haynes 900 rpm - once engine warmed - is that ok? - or does idle need to go down a touch too?

thanks for any comments -

Idle mixture runs through an idle jet......true running mixture runs through the main jet. Adjusting the mixture at idle adjusts the idle mixture! ONLY.
When looking at the plugs properly......run until hot, drive at a constant speed (50mph's about right) push in the clutch and turn off the engine, stop and remove the plugs.....the spark plug colour will now give a true indication of RUNNING mixture.

Martin

will do -
thanks for your comment -

on my pierburg 2e3
i've got a long idle screw facing me - which i assume i move forwards or backwards once the engine is warm to increase or decrease the idle speed revving to clear the carb intermittently - and try and get it to 900 plus or minus 50 - rpm -

just underneath - set in a recess on the left is my mixture screw that works the fuel air mix - this is the one i imagine turns in or out depending on if the colortune is reading yellow or pale blue - 'bunsen burner blue' seems to be the colour to aim for according to the booklet -

makes sense?

do the same at higher revs (2000) to get the mix right - across the range?

Yeah you pretty much have it......
Colourtune can be a reasonable method of setting up idle mixture but as I say this is seperate to the actual mixture at speed.
The main points are that the idle hasn't been speeded up using the butterfly stop and that you don't have air leaks (which will increase idle) from worn components.

Martin

cheers
thanks for that -

i've had a good spray round with carb cleaner - and havent noticed a change in engine speed - which seems to rule out an air leak -

i'll post how it panned out shortly -

thanks again for your comment -

Red Westie wrote:Idle mixture runs through an idle jet......true running mixture runs through the main jet. Adjusting the mixture at idle adjusts the idle mixture! ONLY.
Martin

Actually the idle circuit controls the mixture up to around 3000 RPM when the main jet takes over. It's just adjusted at idle via the CO screw.

I think we will agree to disagree on that one......

Martin

Well Pierburg seem to think it does.

I have a similar background to yours and although these are nice pictures your statement was/is still a little bold and not altogether technically correct.


Your statement: Actually the idle circuit controls the mixture up to around 3000 RPM when the main jet takes over.

Well it contributes it doesn't control...there is a difference and if you read the explaination on the pictures it clearly states it.

The influence the idle circuit has becomes progressively less depending on throttle position and pressure in the intake manifold.
It never mentions the engines revs or that the idle mixture circuit controls the mixture.

However, it does state: The fuel metered out by the main jet forms, with the air from the air correction jet and that at part throttle The idling mixture drilling and the progression slot are ALSO supplying mixture Thats hardly controlling it!

bigherb...we are both on the same side trying to offer the best advice to those that need it. Sometimes I read technically incorrect information on here and it makes me crindge. It's so easy to be on the offensive because you just don't know the level of experience or otherwise of those that are posting.
My replies were a little simplistic admittedly, all I was trying to do was to keep the replies simple and rellivant to the original question.

Martin

Red Westie wrote:Before we get into a pissing competition....

Too late you've just started one by your response.

Red Westie wrote:I think we will agree to disagree on that one......

My very low key response to the initial statement was my atempt at not getting involved....have another read.




Martin

thanks for the contributions people -

its really great to receive a range of comment - and make an informed choice from there -

all appreciated -

colourtune went well - a straightforward - replace spark plug with colourtune - adjust lixture screw so colourtune flashing 'bunsen burner blue' -
job done -

one more off the list! - still have a 'hesitation' moment - (see other thread) - but - getting there -