need help with 66 afb!!

[mikebee]

guys/gals...here's what i got...66 barracuda s 273 4 speed afb i rebuilt.upon reassembly i noticed that the rear jets were 2 different sizes,i thought it was strange,but put it together anyway.

to make a short story shorter it has a dead spot right off idle...i'm no carb expert but i can't see how the rear jets could have anything to do with that.

any ideas on what could be the cause?

i got the rebuild kit from o'reilly's...looked like a nice kit,and carb was very clean inside.

any help is appreciated,
mike bee

 

[RedFish]

Could be a slight delay in accelerator pump. The S link pushes the pump shaft at an angle. Over time this wears the pilot hole and the bore.

 

[mikebee]

Could be a slight delay in accelerator pump. The S link pushes the pump shaft at an angle. Over time this wears the pilot hole and the bore.

could you bend the rod for adjustment?i've tried all 3 holes with no change.i guess there's no easy fix for the pilot hole being wore...the pump seems tight in the bore,and starts squirting way up high...

 

[hotstuff1]

might be low float level

 

[mikebee]

might be low float level

i set floats as directed....how would that do it?unless it was to high and flooding some....it's only rich acting when the choke is on,just for a few seconds...maybe a minute.

 

[jos51700]

On dual-plane manifold, I could see using two different jets side-to-side.

I'd double check that accelerator pump, make sure you didn't fold a lip or cut it.

Also, is it rich enough at idle?

 

[65Val]

"X" however-many on the accel pump...also check for vacuum leaks, and enough initial timing.

Rear jets should have nothing to do with a tip-in bog

 

[67Dart273]

Also, have you checked, "do you know" for sure it's the right carb? There are many variations of old AFBs, and some off GM, etc, MAY have base vacuum leak problems when installed on a different manifold.

Of course even if it's the right carb, it could have a base leak.

 

[RedFish]

When I bought a kit for 67 AFB 4305S I found the 2 needles at the float were same as OEM but the 2 new seats were much taller. It took some creative bending on the floats tabs and altering the slosh baffle a little to get it to where it would work properly.
I doubt this is relevant to you current problem just saying.. you cant trust any aftermarket parts to be exactly right today.
Good luck

 

[Rocky_JS]

rear jets should be same size, but shouldn't be causing an off idle stumble.

That Carb should have a high top cover (not flat) with a 3 step rods and deep/tall jets on the primary.
If they have been replaced (sounds likely) with a 2 step jet or rod or both and the tops are still high top (not flat) that will cause the metering rod to come out of the jet too far and create very poor mileage, stumble etc.. If it has been modified to a 2 step jet/rod you need to make sure it has all been converted for it work correctly.

if the spring is to soft/hard or the metering rod pistons are worn out it can/will not work correctly.

View attachment 66 afb info (1138x512).jpg

 

[mikebee]

thanks for all the input....gives me something to check.it does have the tall primary jets...i'll check metering rods tomorrow.

it is the right carb according to gg book.

the stuff in the kit looked just like the pieces i took out...down to the pump.
i compared all parts...all were identical.

i'll check back in and update tomorrow,and thanks again,
mike

 

[Rocky_JS]

Mike those snips I posted are from the 66 service manual. If you can mic the rods and get the number off of them 16-***

 

[mikebee]

well...i think i got it fingered out.i replaced the tank and sending unit,butt like a dumbass..not the fuel line.

pulled the carb back apart and there's fine rust partestickles all in it.i new i should replace the line!
im gonna clean it again and put a new line on it and i think it will be fine.

it looks like the metering rods are right and there's not excessive wear in drum holes or pump hole.it has been getting worse and now the acc pump it squrting out one side strong but delayed and the other side barely squrts...

i think when i clean it out and get the new line on it'll bee fine.if not i'll be back.

thanks again for the help...

mike