Bog Creature

[billschroeder5842]

Well, I mostly have my charger running well. it is a 383 with a 750 Holley with a vacuum secondary.

what I have now is a pretty good hesitation when I punch it under load.

I'll be cruising at about 2500 rpm and I punch it and the car will hesitate/bog/die for half a second then recover.

Any thoughts? I "think" I adjusted the accelerator pump correctly....

Thanks!

[Ghoste]

Wrong diaphragm spring in the secondary canister?

[MSRacing89]

What Power Valve are you running in the carb?  A mild built 383 with good vacuum should be running 6.5+ power valve.  I would check that first, then move to the secondary spring.

[Ghoste]

Also worth knowing, did you buy the carb new or used?  Was it modified if used?  What cam is there for the accelerator pump?

[billschroeder5842]

Sorry, I don't know about the power valve....don't know where to look.

the carb is stock out of the box. I adjusted the accelerator pump according to (what I thought) was specs and adjsuted the floats.

Is the bog caused by too much gas or two little? I once (once) recently got a back fire on start up (never happened before) but nothing since.

Any adjustments I can make?

Thanks!

[MSRacing89]

Adjustments??  There are always many adjustments.  Tell us where your timing is at.

Laying down on acceleration, from what you are describing is not enough fuel at that moment.  The correct power valve will help allow fuel flow earlier as the vacuum changes in the motor.  You generally want to stay within a few inches of wherever your vacuum is at idle (always up for debate, but let's stick to the basics).  Say you have 10" of vacuum at idle, then put an 8 power valve in there or 7.5.  If you take the front bowl off of the carb, you will find it on the inboard side of the metering block.  Start there.

Example, when I ran a carb, my car had 7" of vacuum at idle so I ran a 4.5 valve.

[Cooter]

I'd be looking into extended squirters Bill.

[maxwellwedge]

Sorry, I don't know about the power valve....don't know where to look.

Answered - On the metering block behind the front flot bowl.

the carb is stock out of the box. I adjusted the accelerator pump according to (what I thought) was specs and adjsuted the floats.

Is the bog caused by too much gas or two little?

Usually too much air - not enough gas.

I once (once) recently got a back fire on start up (never happened before) but nothing since.

That one back-fire may have blew out your power valve.

Any adjustments I can make?

Thanks!

[Dino]

Backfire is an indicator of a too lean mix is it not?

[billschroeder5842]

So here are some specs....

Holley 750 out of the box. Vacuum secondary, electric choke.
Timing is a 12 degrees. any more and I break up around 3500 rpms. New factory dizzy.
Rich/lean... I screw the adjusters in till the motor begins to run rough, then I back off one full turn.
Accelerator pump is adjust so there is a ever so slight pressure on the lever.
RPM set about 800 at idle
Vacuum gauge pulls a steady 15.5 at idle.

I do get a slight hesitation on take off about 1100-1200 rpm. After that, she is a rocket.

[Ghoste]

Assuming fuel pressure and floats are right, then I would be think Cooters suggestion about squirters is next.

[daveco]

This will cost you $14.00.

http://www.ebay.com/itm/1976-HOLLEY-CARBURETORS-MANIFOLDS-BOOK-/150969043484?hash=item232674ca1c

Buy it.
Read it.
Read it over and over and over again until it all makes sense.
Make car go fast.

[MSRacing89]

So here are some specs....

Holley 750 out of the box. Vacuum secondary, electric choke.
Timing is a 12 degrees. any more and I break up around 3500 rpms. New factory dizzy.
Rich/lean... I screw the adjusters in till the motor begins to run rough, then I back off one full turn.
Accelerator pump is adjust so there is a ever so slight pressure on the lever.
RPM set about 800 at idle
Vacuum gauge pulls a steady 15.5 at idle.

I do get a slight hesitation on take off about 1100-1200 rpm. After that, she is a rocket.

Power valve? It is not going to fix itself!!  Just telling us your settings and not actually following up on any advice......anyway I think you get the idea....sorry for the rant.

You have lots of vacuum and should be running a high power valve....can just about guarentee that is your issue.

FYI.  You don't have to go to a full turn on the idle screws after stumble.  Back it out a 1/4 to 1/2 turn.

[Chippa]

So here are some specs....

Holley 750 out of the box. Vacuum secondary, electric choke.
Timing is a 12 degrees. any more and I break up around 3500 rpms. New factory dizzy.
Rich/lean... I screw the adjusters in till the motor begins to run rough, then I back off one full turn.
Accelerator pump is adjust so there is a ever so slight pressure on the lever.
RPM set about 800 at idle
Vacuum gauge pulls a steady 15.5 at idle.

I do get a slight hesitation on take off about 1100-1200 rpm. After that, she is a rocket.

Power valve? It is not going to fix itself!!  Just telling us your settings and not actually following up on any advice......anyway I think you get the idea....sorry for the rant.

You have lots of vacuum and should be running a high power valve....can just about guarentee that is your issue.

FYI.  You don't have to go to a full turn on the idle screws after stumble.  Back it out a 1/4 to 1/2 turn.

Dont waste your breath.......help has been offered many times and none of it seems to get taken onboard......then the same prob in a new post will pop up in a month or two....

Sorry to have this attitude but i'm obviously not the only one seeing this