Hello,

I have a Holley 4160, 600cfm on my 1976 f-100 with 360/FMX combo. The carb is fairly new and I have been making fine adjustments, mainly the accelerator pump. I just got it to where I liked it and now the carb does not want to idle properly.

The truck, cold or warm, will begin to idle at where ever I set it at. Then after I drive it a bit, and apply the brakes and the idle dips below 500 rpm and does not recover, sometimes stalling out. It just recently started to do this. I have also noticed that starting is quite hard now when it is cold or hot. Before one or two cranks was all it needed. It started really good, now it takes 5-10 cranks, even if it has just sat for only 5 minutes. One more thing that just started is that when adjusting the primary idle screws I can bottom out both screws at the sametime and the truck will keep on running. It actually runs better with both screws leaned in all the way then say 1/2 a turn out. The truck idles too rich, but I have no further adjustment to make. I know that I should be able to stall the truck by closing both idle screws, but can't.

Any help is appreciated, I have looked at my 2 holley books but can't seem to find the answers I need.

Rod

 

Sounds like a vacumn leak idle curcuit)

 

Possible blown power valve, or high float level/ needle valve not closing all the way. With it running at the lowest speed it will run at, look down the carb. If you see gas dipping out anywhere, there's a problem.

 

I checked my power valve by hooking up my mity-vac and giving it vacumn and it opens around 7. And I also checked my float level with the sight plug and it was good. i will check it for gas dripping tonight.

 

I looked in the carb and gas was dripping down in the secondaries. I had never set the secondary fuel bowl. I just assumed it was right from the factory. Made the adjustment, now it idles properly