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Brumby mixture
Posted: Wed Aug 05, 2009 4:37 pm
by scoobymine
Having a bit of trouble getting the mixture right. plugs are very light on the electodes.which would normally indicate a lean mix. Normally i'd do it by ear, but this time I used a colour tune kit and the screw is a fair few turns out. Are the standard carbies normally hard to tune?
Thanks
Posted: Thu Aug 06, 2009 10:05 am
by steptoe
that screw is only for idle mixture of which most don't do too much of so not as important as your cruising or load mixture which is from all those air bleed jets and power jets and main jets in the carby which most wil not bother playing with in a normal hitachi carby, play with a weber is a bit different.
Interesting to see you use one of those colourtune devices from the eighties. I have one never used it and only have one size spark plug end.Might have a fiddle one day.
Posted: Thu Aug 06, 2009 10:52 am
by rubisubi
I tuned mine about 6 months ago, set the timing to 10 degress so i can run it on premium. idle was set at 850 from memory and then the fuel mixture i turned in until it started running rough, then undo it until it idles smoothly. Mines never run better, starts firts pop and i get around 10l/100 kays. Don't forget that when you adjust your timing to disconnect the vacum hose and block it off. Cheers Rubi Subi.
Posted: Thu Aug 06, 2009 5:13 pm
by scoobymine
Thanks Guys, the colour tunes are quite interesting to use. They are supposed to go from yellow (rich) to whitish blue(lean) bunsen blue is supposed to be correct mixture.
I do like to tune the old fashioned way, but this device can pick up engine and fuel problems too!
Posted: Fri Aug 07, 2009 12:29 pm
by brenton
i thought i heard that you cant really plug read any more due to the leadless petrols and the old tricks only worked on cars running leaded petrol to get a proper reading of them?
cheers brenton
Posted: Sat Aug 08, 2009 10:06 am
by steptoe
colourtune is not plug reading - it is a special spark plug that is made of a 'special' clear material body so you view the colour of combustion as it occurs!
Posted: Sun Aug 09, 2009 5:51 pm
by brenton
cool let us know who it goes, cheers brenton