Hi everyone this is my first post on the forums so i hope i have it in the right place. I'm trying to track down two issues.

First issue im having is a really bad hesitation or bog when i stab the pedal. Depending on how far i push it it will act like the motor dies then a second later it starts to come to life. To me it feels like accerator nozzles need to be bigger.

Second is after i get out of the throttle i get a back fire out the back of the exhaust. I believe it just running pig rich.

Run down on the car. 440 block eddy RPM heads,1.6 rockers, mild cam. 9.5 to 1 compression, single plane eddy intake 850 demon carb. 2500 stall with 727 manual valve body with 4.10 gears. I have MSD everything coil,disy,and box.

I have the distributor set to 12 degree before TDC. stop plug is 26 or 28 degree so total timing is around 38 to 40. I have the lightest springs installed im all in at around 2,200 rpm. Ive check my wires everything looks fine except for number 5 cylinder is pretty tough on plug wires header seems to chew them up.

The carb has never been opened since it came from the factory until a few days ago. She runs rich. So just playing with the carb it originally had 73 prims and 80 secondarys i dropped one jet size up front and two out back so it has 72 and 78. Which i feel is still pretty high but this is my first carbureted car so im learning a little.

 

Double Pumper? Or Vac Secondary?

Do you or one of your buds have a 750 Holley you can try....
Double pumper or Vac. Secondary?

I think you too fat? Does it puff black out the tail pipe?

 

Well the 850 demon i have is a double pumper. I do have a old 750 Holley double pumper. But i always had a problems trying to get the holley to run worth a damn.

It does puff a little black and the plugs are black.

 

Ok...Let work with your 850 for now then... Does the 850 have the large Accel pumps or the smaller ones?

 

Give it 2 degrees more advance and see if it makes a defrence.

 

ok... I see you ducked out....
I am going to assume that you have performed all the adjustments in the instuctions,,,,

Here is my 2 cents at this point...

4 Corner idle screws are all even....
Set all 4 corner Main jets to 68 Square....

See if that cleans it up enough.....?????

Keep us posted....
Welcome to the site....

 

salty -

Yes, sounds like you're over carbed and it's made worse by the single plane manifold (which is really for top end).
.
Yes, leaning down the carb should help, and if you have hood clearance install a 1" 4-bore spacer between the carb and the manifold.

I think it might help (just don't ask me how I know...)

Archer

 

Thanks Racerhog for your help.

Today i decided to pull all the plugs last time i looked at just a couple of the plugs. I replaced with new plugs. They were all black except for 7 and 8 had a little brown mixed in with the black. And number 6 which is the trickiest plug to get. looked a little wet. After inspecting the wire i found two spots cracked in the jacket. This might be the cause for the back fire in the exhaust. I wrapped some elctrical tape on the spots to help. In the end it just needs to be replaced.

I thought i had adjusted the 4 corner idle equally well that was not the case. Shop gremlin must have tweaked it when i wasn't looking. I screwed all of them back in. Then backed them all out 2 turns. Fired up the car put the vacuum guage on the manifold port. Started cranking them all equally in till i got the best vacuum reading i could get 15 inches. Also changed the main primaries to 68. I took it for a spin the bog or hesitation was still their but seems less pronounced. I was also fighting an ignition issue drop a cylinder or maybe 2 it was running like crap. By the time i got it back to my storage unit i was just ready to go home wasn't in the mood to burn myself or wait for the headers to cool off. I will take a look this week to see about fixing the ignition issue. I will keep you guys posted.

Thanks again guys for your help.

 

Sounds like your gaining on it.... Adjust the secondary Jetting to the same as the front... This way your not chasing it.. Get her leaned back out.. then we can sneak back up on get her fattened back up...
Once you get the ignition checked up, and the timing reset, and the carb a little closer... Then will look at getting rid of that bog your looking at.. Never over until the fat lady sings....


Keep us posted...