Carb problems!!!!

[0ld69er]

My 69 GMC with a 400 sb has a 650 Edelbrock AVS thunder carb with a bad hesitation on the throttle being slammed to the floor from a dead stop.it stumbles bad then takes off,and I bought the kit for the metering rods and jets and tryed all kinds of combinations and bought the accellorator pump nozzels and changed them up and down but no change,changed the position of the acc pump lever too but no real change,if anybody has any other suggestions give me what you think.

thanks old69er

[Tkmadone]

Retarded timing can also give a bad hesitation. I would double check that.

I'm not too familiar with the Edelbrock carbs but is the acc pump a diaphragm? Could it be ripped?

[Husker]

Check your timing, I had the same problem set timing fixed the problem.
Ron

[0ld69er]

Thanks guys but yes I did check the timing and it is good.

[dznucks]

Whats your timing set at?

you may need to open up your accel pump squirter. you can buy larger ones or you can use a needle drill and drill out your exisitng one.

can you pull one of your plugs and see what color the electrode is? if it is white, with minimal tan, you are running too lean and you are getting a lean spike off-idle. you will need to richen your cruise side.

i had a 1406 600 cfm edelbrock that i had similar problems with. i had to go to a calibration point off the charts.

[fdbdw]

Have you tried adjusting the secondaries, if you or PO has played with the adjustment it might be out of wack, . The manual has directions to get it back to the stock setting, I would get it back to that setting and do a trial run, if it still happens make small adjustments counter clockwise (opens sooner) about a 16th of a turn on the adjustment scew at a time with a trial run each time, if you can get a full half turn and its still happening go back to the stock setting and do the same thing with 16th turns clockwise. If that doesnt fix it, it will at least alliminate that possiblity, but its very important to find the stock setting first. You should be able to find the 1806 AVS manual on line, if not let me know , I have one and can walk you threw it

[68Stepbed]

That's why I call them Edelburp carbs. Every one I've had does that and never could get it tuned out.

[BIG69GMC]

i know it sucks cuz im working on the same thing now with a new quad. i found i was running a little too rich, but after it warms up really good it starts doing it again. i was going to check the timing (which is good) BUT im going to try advancing it, after all i did replace the dist. too and have found it lost its top end. so try advancing it a few and play with that and see what happens. i will be doing the same. best of luck!

[0ld69er]

I bought the kit for the squirter and found I had a 31 in the carb and went up to a 33 and no change then went down to a 24 and still no change,so now I will look into the secondarys thats the only thing I haven't touched.

[0ld69er]

If fdbdw can give me a rundown on how to adjust the secondaries that would be great,I can't find it in the online manual but I do remember reading about it in the manual that came with the carb.

thanks all old69er

[fdbdw]

On the throttle linkage side of the carb there is a set screw that holds down a larger flat head connected to a rod that runs across the center of the carb. Put the flat head in place before loosening the set screw so it doesnt move on you, loosen the set screw then turn the larger adjustment screw to desired setting ( in your case small turns, with test runs) keep ahold of the adjustment screw in the position you want it until you re-tighten the set screw, thats it, good luck.

[youhaveamonkey]

I agree with ALL of what is posted above, it is also worth checking fuel filter(S) sometimes they can do VERY strange things if they are even slightly plugged up. Granted, I have never owned an edelbrock. I have owned a couple of these trucks and found that, with old fuel lines, sometimes you can disturb sediment or other debris that can plug up a fresh fuel filter. Worth a look?

[willys72fleetside]

You also have to make sure that the mixture screws are properly set, if they are not it will cause a hesitation in any carb. Use a vacuum gauge or tach to set, turn each screw untill the maximum vacuum is reached or untill the max rpm is reached. With the edlebrock (carter) it is usually around 1/2 to 1 turn out. Good luck

[BERT306]

Do u have vac advance and what mechanical advance springs are in your dizzy? might need to check your total timing if you're just checking base timing at idle.