holley 80457 wont idle

[lowbush]

Guys,

I am trying to get my truck on the road and am getting to the last little details one of them is when I start the truck it will not stay running at idle, once it is warmed up it will run fine but cold it dies if I take my foot if the accelerator, if I give it just the littlest bit of gas it stays running, also the truck is smoking a lot. I think the mix is too rich but I don't know a whole lot about carbs so I need some guidance on what I should be looking at. I know to check the vacuum but should I try to lean the mix if up the idle. I don't know the best way to approach dealing with the issue.

 

[PaveBronco]

if its been sitting awhile the card prob varnished up. needs a good cleaning. and the choke's not working

 

[broncnaz]

Ditto on the posibility that the choke is not working correctly. Along with maybe the idle mixture screws need to be adjusted. As was said probably some varish in the carb that is causing the issue. Id bet its mostly the choke since it runs fine when warmed up.

 

[lowbush]

Sorry forgot to mention I busted the whole thing apart and cleaned everything up it was definitly varnished and the primary diaphragm was shot, so it was leaking. I got all that squared away.


So I adjusted the idle screw and now it is idling just fine, but the truck is still smoking to high heaven.

 

[broncnaz]

What color of smoke? Black, grey??

 

[lowbush]

What color of smoke? Black, grey??

grey smoke

 

[broncnaz]

Have you rechecked the float levels? Also look down the throat of the carb while its running is fuel dripping?

 

[broncnaz]

If the float levels are good. You may need to pull the front bowl and metering block off and make sure you the powervalve is tight and has a gasket on it. Might also make sure the metering block gasket is correct and in good shape.

 

[Fairlane514]

Start with the idle mixture screws turned out (from all the way in) 1 1/2 turns. Use a vacuum gauge on a full manifold vacuum source and get the highest reading you can by slowly turning the screws a half turn. If you turn them out and it gets worse then turn them in and vise versa, until it's right.

Both screws should be at the same adjustment when done.

 

[lowbush]

Start with the idle mixture screws turned out (from all the way in) 1 1/2 turns. Use a vacuum gauge on a full manifold vacuum source and get the highest reading you can by slowly turning the screws a half turn. If you turn them out and it gets worse then turn them in and vise versa, until it's right.

Both screws should be at the same adjustment when done.

yeah the manual keeps saying that those are set from the factory and should not be adjusted so I wanted to get recommendations from here, before I started putting my monkey paws on it.

 

[PaveBronco]

Adjust away...I assume the plugs, wires, coil, cap and Rotor, filters, and Timing are all OK?

 

[pcf_mark]

If it runs fine when warm then your idle mixture is close enough and you do not have any vacuum leaks. As someone pointed out check that the choke is operating. Is it closed when the engine is off and cold? If so can you adjust it to open more slowly (there is an indicator on the choke housing) and does that improve your situtation? Is the fast idle adjusted correctly? Most Holleys the fast idle is set almost the same as curb idle and the screw is a total beaatch the get at. If your rig is an A/T you need the fast idle to be working or it will die.

This example is on a Chevy but the photo of the fast idle screw is priceless

http://www.hotrodders.com/forum/holley-carb-fast-idle-adjustment-219247.html

 

[lowbush]

Choke is fine and idle is fine now, I did look under the car and noticed what I thought was oil dripping out of the headers where they join to the exhaust. After inspection it looks to be unburnt fuel mixed with carbon, it's too thin to be oil. So I think the thing is running really rich. I am pretty sure the timing and all those other items are fine but I have not put a light on it, but as I said it ran when parked so I don't suspect the timeing is out of whack, the only work that was performed while parked was body work, wiring harness, and transfer case work. So the engine should be the same sans sitting for an extended time.

 

[broncnaz]

yeah the manual keeps saying that those are set from the factory and should not be adjusted so I wanted to get recommendations from here, before I started putting my monkey paws on it.

They are preset to a baseline setting that doesnt mean they are correct for your engine. Many times you will get better idle quality if you adjust them to your engine. But if the engine is smoking Im pretty sure that the idle mixture screws are probably not the cause of it. It takes way more fuel to do that than the idle system supports. Just another thing to check before you pull the carb apart recheck the float bowl screws make sure they are tight. If they are loose the gaskets may not be sealing properly.

 

[pcf_mark]

What are the current symptoms? This started with poor idle when cold and running fine when warmed up. Now it sounds like you said the idle is fine.

If it is running rich you can cheat a bit and pull off a vacuum cap and leak in more air. This will lean it out. If the idle goes up and smooths out you are too rich. If it stays the same or dies you are close enough.

As Bronconaz said you would need to have a serious fuel leak like a float too high other internal carb problem to poor that much fuel out if that is what it is. At cold temps the engine is making a bunch of water vapor and that is probably what you are seeing dripping mixed with fuel and carbon.

 

[lowbush]

current symptoms are it starts and idles now, but it smokes a lot, the smoke is grey, it has a strong smell of fuel and I believe that unburnt fuel is washing out the exhaust because I am getting a drip from the header when the truck is running, it is black like oil, but is as thin as gas and smells like gas. I think it is just black because it is picking up carbon.


When I check the float levels how level does the truck need to be, it is in the driveway now and sitting a probably a 5 to 8 degree incline. Just wondering if I need to take it down to the street and level it out or is it not that exact of a science. It's been years since I have done anything with a carb and when I did it was old VW air cooled engines so I am relearning all this crap yet again.

 

[Fairlane514]

Get it as level as possible when checking the level. It should be just below the threads on the sight screw hole.

Do you have a PVC hooked up? Do you have baffles in your valve covers?

Im sure your plugs are fuel fouled by now.

 

[bmc69]

Don't be afraid to adjust the fuel level so that it is solidly below the sight holes; no weepage. I typically adjust the level to be almost roughly 1/8" below...and am happy if a bit of fuel sloshes out the hole when I really give the truck a good shoulder bump and I can otherwise see it through the sight hole.

Another suspect for excessively and chronically rich operation is a leaking power valve.

One of the most overlooked problems is excess fuel in the secondary bowl that flows over a bit and pools on the butterflies...leaking past them randomly and without any additional air added. The secondary side is the one that I always make sure the float level is set a bit below the sight hole.

 

[pcf_mark]

Also pull your dipstick and see if it smells of fuel. If so then your fuel pump diaphragm is leaking and fuel is getting into the crankcase. Maybe as the engine warms up it evaporates and ends up going in the PCV and out the tail pipe. Just guessing but a quick check.

 

[lowbush]

Yes plugs are fowled now, but I went ahead and replaced them with new ones and those fowled as well. checked the level and it was below the line no spillage and sitting about 1/16 below the hole from what I could tell. I hooked up a brake bleeding pump to the vacuum and tried adjusting the screws but the gauge was jumping all over the place, the gauge was just not sealing well is my guess. But even though it was jumping around I did not really see the vacuum improve by adjusting the set screws and I ran them all the way in and then started working them out. Seemed about the same no matter where I put it.


I will have to look at the PCV valve, it does have a oil breather on the top of the valve cover, but I don't recall checking the PCV valve. I will take a look tomorrow.