Greetings,

I just got rid of my 1405 edelbrock, and now I'm temporarly running a holley 600, 4160 type. The other day it took a complete dump on me, went from running great, to barely idling, sputtering, and max lean on the a/f gauge. Throttle response was gone too. Barely driveable.

Before this I was pulling a steady 15in+ of vacuum,the dial wasn't even fluttering, with no bogs anywhere and no hesitation. Both floats were also set right under the holes, shaking the car would drip fuel.

So I began my troubleshooting; mixture screws, idle speed screw, accel. pump lever, blah blah blah. Nothing major.

Floats were last on the list, because i had just set them last week. So I dug in to those finally.

So to find out, the secondaries were dry, so i pulled out the needle and seat. Lo and behold there's half an o-ring wedged in the recess. Cleaned out the o-ring, and reinstalled the N/S. Immediately upon startup the a/f gauge jumped back up to rich, and fuel could be seen in the bowl.

I'm pretty sure i fixed it, but I don't understand why the secondary side needle and seat being jambed, would effect idle, tip in, and everything else?

Somebody fill me in?

btw, 4160>1405

 

AFAIK, a 4160 (VS) should not have any idle fuel mixture adjustment, but still has the air bleeds, transfer slots, and metering plate to control secondary idle fuel. If the secondary TV stop is adjusted slightly open, you'll get idle fuel. Without fuel in the bowl, it'll be lean.

 

Yeah, the secondary side of a Holley VS carb still has idle circuits (curb and off-idle)- they're just not adjustable with mixture screws like the primary side is and they generally don't meter much fuel. The vast majority of the idle fuel comes from the primary side- but not all of it.

 

alright, thanks guys!