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Air Fuel Ratio

PostPosted: Thu Mar 31, 2011 2:20 pm
by Tonyw
Hi all,

Just wondering if any of you have used a Gunson Gas Tester to check your fuel ratio? I note that some of you have used Gunson's colour tune.

I have a couple of NOS Strombergs which have the mixture adjustment screws at the bottom of the carb float bowl and I am keen to get the fuel mixture right, I know I can set them by leaning of until the revs drop of then turn it to rich a little but I would really like to put a bit more science into this and also not have to keep taking out spark plugs to look at the colour. The Gunson gas tester do not seem to be that prohibitive cost wise anybody.......................

TIA
Tonyw

Re: Air Fuel Ratio

PostPosted: Thu Mar 31, 2011 3:38 pm
by john.p.clegg
Tony

...or even the infra red digital thermometer some of us have picked up recently?

John :wink:

Re: Air Fuel Ratio

PostPosted: Thu Mar 31, 2011 5:09 pm
by tdafforn
Hi
An AFR meter is a great tool. I have used the gunsen but one if the newer systems like the innovate system are much better. Colourtune is a bit of an art. I always found that I had to run with a yellow flame.
Infrared thermo helps with checking for a lazy cylinder.
Cheers
Tim

Re: Air Fuel Ratio

PostPosted: Thu Mar 31, 2011 11:29 pm
by elansprint71
Zetec? :twisted:

Re: Air Fuel Ratio

PostPosted: Fri Apr 01, 2011 5:44 am
by john.p.clegg
I find mine likes 13:1 (it definitely doesn't like 14.7:1)for tickover and am trying to wean it down to 16:1 for cruising...

John :wink:

Re: Air Fuel Ratio

PostPosted: Fri Apr 01, 2011 6:24 am
by Tonyw
John,

So how are you measuring your AF ratio??

Tonyw

Re: Air Fuel Ratio

PostPosted: Fri Apr 01, 2011 8:42 am
by john.p.clegg
Tony

Have EFI fitted controlled by Megasquirt,and a WBO2 lambda sensor just after the Y-piece.

John :wink:

Re: Air Fuel Ratio

PostPosted: Mon Apr 04, 2011 12:03 pm
by tdafforn
John,
What ignition timing did you settle on in the end?
Tim

Re: Air Fuel Ratio

PostPosted: Mon Apr 04, 2011 3:05 pm
by john.p.clegg
Tim

I have a map,Revs/Throttle......will try to lift it

John :wink:

No,I'm an I.T. Idiot

Lets try posting the file....the extension vex is not allowed??Try changing it...Bugger

Re: Air Fuel Ratio

PostPosted: Mon Apr 04, 2011 3:08 pm
by john.p.clegg
Tim

Even tried PM'ing you but vex is still not allowed...

John :wink:

Re: Air Fuel Ratio

PostPosted: Mon Apr 04, 2011 3:13 pm
by john.p.clegg
Sorry for diverting the thread...last try...Tim,it's here

http://www.msextra.com/forums/viewtopic ... 72&t=40035

John :wink: