holley 750 carb issue

[funnycar]

have a 451 engine Holley car 750 dp.
start runs fine till we stop and when you go you have to kinda 2 step it to get it going.anything after you n2 step it runs great its the stumble that's the issue.
I had a 30cc accelerator pump in it and installed a 50cc complete kit in it.
have the the adjustments made on the lever that activates it to the pump and the plastic cam.
no vacuum leaks checked that
power valve ?
metering block?
im stumped
thanks

 

[lewtot184]

go back to the 30cc pump with a more aggressive pump cam.

 

[HEMI-ITIS]

Check that you have the right power valve.

 

[funnycar]

thanks
yes had the cams change no help
power valve next

 

[coloradodave]

What accelerator pump shooter is in the carb? # will be stamped on it. Has this always happened or is it a new problem, and, if so, what was done to the motor before this started?

 

[Meep-Meep]

A 750 DP should work on that engine pretty much out of the box so check it and make sure you have the factory jets, PV, accel pump hardware, etc.. Float settings also must be correct. Then check your timing. You probably have a hot lumpy cam so set total advance to about 36 deg all in by 2500 and initial at maybe 15 BTC. Vac advance should be used and hooked to the ported port. The point is your advance curve, which is RPM dependent, should be pretty fast - the timing mark should advance quickly as you increase the RPM. Make sure all that is working then we can tweak the carb in.

 

[funnycar]

well im back and I still have a problem with idle
question
when the motor is operating 190 degree she still don't idle but it will idle when the choke is fully closed.
i have done some changing went from a holley dp to a edelbrock carb new plugs pulled the dist and put it all back on tdc
went from single plane intake to dual plane intake
doesn't matter what you through at it it still wants to idle at full choke when running 190 degree
is there something behind the block transmission that has created a vacuum leak ive checked all the intake carb base plates
im just missing something simple
thanks guys

 

[HEMI-ITIS]

Try to get your hands on a smoke machine to find your vacume leak.