Gunsons Gastester

[tim wood]

Hi, has anyone used or of these ? I'm thinking of buying or from eBay and they seem reasonably cheap secondhand.

No good though if they don't improve on the " setting by ear" method
All comments appreciated.

Thanks
Tim

[christopher storey]

Yes, I have had one for years. Mine has worked pretty well for setting up idle mixture . It is less reliable for identifying what happens as the revs rise, but still gives a good indication of any gross problem. On an E with 3 carbs , of course, both pipes are affected by the centre carburetter, so you have to switch from pipe to pipe fairly regularly to see what is going on . I find the best thing to do is to set all 3 jets down by the same amount ( I use 65 thou) as a starting point, and go from there, preferably adjusting each screw by the same amount

[kingzetts]

+1

I've had one for at least 20 years and most recently used it to set up the e-type. When it went to CMC for an MOT and tuneup they reckoned the mixture was pretty much spot on.

[Nick]

If its the same one I'm thinking of, the 'pump' part is secured to the body with double sided tape which softens as the exhaust gas heats it up. Rather cheaply made this part. Also, the calibration can drift so you need to keep checking it.

Nick

[Richard2293]

I have used mine successfully on three classic cars, all with multiple carbs. Start with all carbs checked and set up at same jet height, then adjust all the same to reach correct exhaust levels. Only "snag" is to get the gas tester "pump" to oscillate. Works well on straight exhaust pipes, but V12 fan tail took a while to find the correst place in the tail pipe. My emisssions have correllated well with MOT test equipment. Good luck

[Woolfi]

There is a method to adjust the mixture of multiple carbs , which seems (for me) much better,
One person has to hold a piece of paper behind the exhaus pipe. The second person starts to turn one carb leaner. When the sound of the exhaust strts to make rrrrrrrrrrrrr pop rrrrrrrrrrrrrrrrrr pop rrrrrrrrrrr, you tune this carb 90 degress more fat, until the pops disappear.
Then you start with the second and third carb in the same way.
If you do like this, you have fixed all carbs spot on on the correct level. With a exhaust gas tester on a EV12. you can check only all 4 carbs together.
I am adjusting the mixture on my EV12 6,0 with this method since years and the idle is PERFECT. I can stand a srew 50mm / 6 mm with the thin end on the middle of the motor, when the motor is on idle and the scew will not fall.
If you are driving an you fell a flat spot, you can adjsut each needle 45 degrees more fat.
Somebody with a gas tester should test this method, controll the results with his gas tester and write here in the forum, if the method is good or not.
With a 12 Volt Gas tester you can make tests while driving and check, that the CO is maximum 0,5% when driving quicker than 40 mph.
Still the best is mounting a LC-1 from innovate. With this "gauge" you can check the mixture when driving. This is MUCH more important than the micture at idle. If you have changed the exhaust- or the airfilter-system, the mixture is out of range when driving, but the mixture at idle is okay.
Regards Wolfgang Gatza