Holley issues

[RedZ85]

My 670 CFM street avenger has vacuum secondaries. When i open the throttle, the engine revs like it should, however, if i stap the pedel fast, it chockes up. Like too much gas. I had a buddy watch my secondaies when i stab the gas pedel and he said that they wernt even opening up. Im beginning to thing that i should have gotten mechanical secondaries. Any ideas on what i need to adjust? Is there a way to adjust the amount of fuel pumped through the main jets?

[MONGO510]

The vacuum secondarys will not open much if there is no load on the engine.

[Alf]

thats not very descriptive, what does it do if you are driving and sudenly stab the gas? from what you said it sounds like the accelerator pump discharge nozzels, or squirters. check and see what you have and try the next step smaller. this could also be your accelerator pump cam, the cams can be swapped to get more cc's out of the pump. i recomend getting the "holley carburetor handbook" by mike urich, its very informative. and once you know how the carburetor works its fairly simple to tune it to your engine.

[GrayZee]

thats not very descriptive, what does it do if you are driving and sudenly stab the gas? from what you said it sounds like the accelerator pump discharge nozzels, or squirters. check and see what you have and try the next step smaller. this could also be your accelerator pump cam, the cams can be swapped to get more cc's out of the pump. i recomend getting the "holley carburetor handbook" by mike urich, its very informative. and once you know how the carburetor works its fairly simple to tune it to your engine.

 

 

I agree, sounds like accelerator pump to me. There should be a adjustment for that.

[Mike C]

As noted above, the "bog" is most likely too much air and not enough fuel. First thing to do is rotate the accelerator pump cam to the second hole. This speeds up the pump discharge. Next move up in size with the squirter. Depending on how this works, you may need to change to a different pump cam and yet another larger squirter.

[RedZ85]

As noted above, the "bog" is most likely too much air and not enough fuel. First thing to do is rotate the accelerator pump cam to the second hole. This speeds up the pump discharge. Next move up in size with the squirter. Depending on how this works, you may need to change to a different pump cam and yet another larger squirter.

 

These carbs are supposed to be wet flow calibrated at the factory and ready to run out of the box. I can see some tweeking here and there, however, to have an issue like this seems that something isnt working properly.

[Mikelly]

I've never pulled a Holley out of the box and put it on a motor and had it do much more than (And sometimes not even) idle.

 

The above into posted by Mike C. and others is a very good starting point, but as mentioned early on, how does it do under load? Vacuum secondaries don't open without load.

 

Mike

[dr_hunt]

Wrong, Holley does not wet flow calibrate carbs! The only carb people that wet flow carbs are custom jobs, like Davinci, C&S and others of the like. Holley is a manufacturing plant only. Even holley admits that the flow numbers are "dry" flow numbers and "wet" flow numbers are usually 50cfm lower than the advertised flow rating of the carb.

[Mike C]

Even if they DID calibrate the carb ahead of time, and assuming that whatever engines it was for were all the same displacement, how could it run the same on a 5000# pickup truck with a camshaft having 190 degress duration at .050, 2.73 gears and a 1200rpm converter as it would on a 2800# car with 3.73 gears and a 3500 rpm converter using a cam that's 242 degrees at .050? Radically different fuel delivery, accelerator pump shot, and pump delivery time exist in the above example alone not to mention displacement, compression ratio and altitude! Having run and/or rebuilt nearly 25 different Holleys, one constant is they all need tweaking out of the box.