Holley vac sec question??????

[Charger4404spd]

I havent really dealt much with vac sec carbs, so my question is this. Under full throttle acceleration, Ole Red is very rich (black smoke out the exhaust). I believe I need to go with a stiffer secondary spring. Am I correct in my assumption?


Steve

[John_Kunkel]

The spring only controls the opening rate of the secondaries, it doesn't control the mixture.

The fuel mixture is controlled by a jet plate in the rear fuel bowl. A bad gasket or too high floats will also make the secondaries run rich.

[Just 6T9 CHGR]

Heres a nice refrence site....
http://www.bob2000.com/carb.htm

Been doing some "super tuning" with my 750 as well.... 95% there on removing an off idle stumble in mine.....
playing with higher power valves.

I also just ordered up a ProForm main body for it as well.  I have read a lot of good things about the piece and with me dropping my aircleaner, the added feature of a milled choke airhorn to give me more air flow is a plus

[Charger4404spd]

Very good article. Thanks guys!

[darrin75]

At WOT how much should the secondaries open??All the way?  A little bit?

[Steve P.]

At WOT with a MS carb they should be wide open. With a VS carb it is harder to tell as the carb opens the secondaries according to the motors needs.

To tell it the secondary is opening all the way you will need to place a paper clip on the vac. pod. rod and take the car for a good blast. Then once you are back at home, shut her down and pull the air cleaner. Then move the rod, (NOT MOVING THE CLIP), to where the clip just touches and look at your secondary blades.