slight stumble off ide

[steamer]

17080202 carb on 350 with 8.2:1 CR. headers/dual exh, 218/224 @.050 cam, eddy dual plane intake, stock heads.
71 jets, 43P rods
Large air  bleeds, .115
sec Hanger F, rods CH
(dont have any bits to measure the idle tube & DC restrictions yet).


what I have done so far
.130 needle & seat
new float set at 1/4"
new sec air valve spring & cam
new accel pump
new choke pull off
mixture screw holes enlarged to .089

The car has a slight stumble off idle when light  throttle is applied.
all other carb functions seem OK
Reading some other posts with similar symptoms it sounds like adjusting the APT might help, but am I rich or lean?

[Cliff Ruggles]

Not nearly enough jet for a large MAB carburetor.  It's going to be lean everyplace.

I just finished up an early truck large MAB model here.  It came from the factory with .078" main jets, and 46B metering rods.  It showed pretty lean on our test engine and required the metering rods be raised up considerably to get the A/F within range.....Cliff

[steamer]

Thanks Cliff, we discussed this carb a bit on the phone but at the time I didn't know what size the MAB's were. Is there any point trying to work with this jet/rod combo or should I start fresh with a combo that offers a larger metering area?

[Cliff Ruggles]

Several ways to go with those units.  With this new fuel, it typically takes .77-.078" main jets to get enough fuel to work with.

I much prefer installing small MAB's and smaller jets and metering rods.  It cleans up the fuel curve and makes them much easier to tune.

We have all the items you would need.....Cliff