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MG MGB GT V8 Factory Originals Technical - How to change Carter jets?

Can someone tell me, step by step, how to change the jets in a Carter/Edelbrock/Weber carb? I mean _really_ step by step! -- I'll try anything but I am hardly the world's most experienced mechanic.

My Carter 400 is running too rich at all throttle conditions. Sooty exhaust, sooty plugs, bad fuel consumption, A/F meter says much too rich. (Car runs great, though.) I am told the Carter 400 came stock with .098" jets, and that I might try putting in .095" ones. Happy to do it, I just have no idea how. I assume they are lurking somewhere below those mouse-ear cover plates. I am wary of just taking stuff apart at random, especially when there are a lot of tiny pieces. Also, what parts do I need, aside from a new pair of jets?
David

I have a competition series carter, but hopefully they should be identical.
These carbs use metering rods and jets for primary circuit and jets only for the secondary.
For the primary side, you can increase the size of the metering rods alone in order to lean out the mixture. If you have gone to the thickest rod available and are still too rich, then you have to remove the jets and exchange for smaller.

1) buy a jet/ metering rod kit.
2) remove air cleaner assembly and possibly fuel line/ but not necessary if you have enough slack in line.
and cover carb with rag to prevent dropping anything inside.
3)simply remove the two small screws on top of the carb. Inside will be the metering rods connected to a spring - remove from carb and change metering jet to desired size and reassemble. Test run to determine if you are still running too rich. If after going to leanest rod, and still too rich, go to next step.
3) remove all linkages from bottom on carb that connect to top of carb. These are the linkages for the choke on both sides of the carb and the accelerator pump. simply remove the pins on top of linkages and carefully let the linkages drop out of way. remove rod in center of carb that holds down air cleaner assembly. remove all bolts on top of carb and CAREFULLY remove top of carb in order to not tear gasket as it may be reused serveral times.
4) inside the carb you will see 4 jets in the float bowls. the two nearest front of car are the primary jets. Unscrew these jets with a flathead screwdriver and remove by inserting a pencil inside the jets an lifting them up. Change to desired size and reassemble and test drive car.
5) the metering rods are stepped and not linear in size from bottom to top and you may have to adjust your idle each time to change rods/jets.
6) test drive car at part throttle so that you meter shows stochiometric ratio of 14.7 or center what ever the case might be.
7) after setting up primary you can go on to secondary and fine tune it. I would suggest an air fuel ratio of about 12:1 for maximum power and to make sure you don't lean out on upper limit of rpm where you might not be able test on road using meter.

hope this helps and good luck.
Joaquin

Thanks Joaquin. I realize the rods are stepped. Unfortunately, I believe I am using the leanest rods now, so I will have to go directly to the jets. The only thing that sounds creepy from your description is disconnecting the linkages and pulling off the top half of the carb. I can pretty easily see myself screwing that up. Then again, as they say, how hard can it be?
David

try it, its dead easy, but you'll need something sharp( pointed test light) to pry the pins off the linkages and try not to loose them as they tend to fly off. You'll be removing them several times tuning in the carb and will become very proficient at dismantalling carb.
JOAQUIN

Joaquin, thanks. When putting the thing back together, should you put Permatex on the gasket or just leave it? ... I can't tell whether there's already some on there.
David

just leave it. remember not to overtighten the screws. The top is aluminum and the screws wear away at the top after many many removals/installations.
joaquin

This thread was discussed between 14/05/2001 and 16/05/2001

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