fuel leak down

[megaladon6]

pontiacgcp; i can not speak for what holley decides to do with their designs. but if you read your link it states that carbs used to have the idle adjustment i described on my carb. it then says that holley began to use a reverse idle adjustment on some/most 4150,4160,4165, and 4175 carbs. this was for emission reasons. this is kind of like the redesign of the q-jet in the 80's to provide electronic feedback control. therefore there are 2 versions of some carbs, emissions and non-emissions just like i said holley told me.

 

[dan2286]

The EFI 95 Sentra I used to have ( before that dumb b*tch in the Rav 4 killed it!) had a similar condition after it sat for two days. It would not start unless you primed the whole fuel system by turning the ignition on but not cranking it then back to off wait 5 sec, on again then start. It had no leaks and I just thought it was a quirk of the car and let it be. It usually got driven 800-1100 miles a week and so rarely ever sat unless I got bored with it and drove the truck for a day. Oddly, the truck, also a Nissan, could sit for a month or two and start on the first crank with no need for priming ( I had stopped driving it daily for 2 years and it sat around as a parts hauler and dump hauler before the accident). My Cutlass does the same thing after about 4 days of sitting and I need to crank it for a few seconds to prime the carb then it starts. So, I dunno. If it were doing this after shutting it down hot then trying to restart it within an hour, you could surmise it was percolation and that you may need a carb heat shield. GM did this on some of its cars using a metal plate sandwiched between 2 carb to manifold gaskets.

On EFI there is some kind of valve or something in the fuel pump that is supposed to hold pressure when shut of. That goes bad sometimes, that is why it needed priming. Im not sure if mechanical fuel pumps work the same way though.