Stalling Problem

[road chicken]

Ok, I need a hand here. I have a 383,750 vac sec holley,( the new ones with no gaskets below the fuel level), on a M1 dual plane. heat risers are blocked off 484/284 mp cam set at 0 deg. Timing is set 10 btdc and idle is @ 900 rpm. The engine at idle, will slowly lose rpm till it stalls. I have to constantly keep bliping the throttle to keep it running. this get real annoying with the 4 speed. Any ideas?? Carb, idle speed/ mixture. If I up the timing or the idle speed much more it starts to get into the advance curve. the car does have a slight hesitation off idle,( presumably do to a small shooter or pump in the accelerator pump. Any help would be appreciated. thanks RC

[MopART]

May be that your float levels are off or that the pump lever doesn't have enough play.

Does it smell like it's running rich ?

ART

[road chicken]

The floats were set to just dribbling out of the plug,i will recheck it. How much clearance should the pump arm have? It burns the eyes when it's warmed up at the tail pipes. Is that rich or lean?? Sorry I'm just geting to learning the tuning on cars.

[MopART]

If it's burning your eyes, it's way too rich.
It's possible that it's stumbling b/c the plugs are near fouling out from too much gas and when you rap on it it clears up.

I like to have about a .015 air gap in the pump lever and the plunger.

Do you know what jets are in the front and back ? Let me know.

This is how I adjust my floats:

Front: fuel should not come out unless I push down on the fender to rock the car. If fuel dribbles out when you remove the check plug, it may be too high, but not so that it will cause this problem. You can adjust that later unless it pours out, then you would want to lower it.

Back: should dribble out like you said it does so leave it like it is.

Do you have idle air adjustments at 2 or 4 points - I think just 2, is that right ?

ART

[road chicken]

The front float level is higher than what you said it should be. The back problably is too. It's a little subjective the way the motor is cammed.Your supposed to set and check this with the engine running, correct? But I will drop them.
The Jets I will have to check on and let you know.My memory is telling me 68's front, 70's rear. The way the plugs look, ( light tan) I believe that is set correctly.
I will set the pump clearance too. That I know is just touching the plunger.
Air adjustment is just 2 points, one on each of the primary barrels. Backed out 2 turns each.
I will get a chance to play with it tonite, and I will let you know. Thanks again.

[This message has been edited by road chicken (edited March 08, 2000).]

[This message has been edited by road chicken (edited March 08, 2000).]

[MopART]

Do not adjust the floats with it running !!!! It's very dangerous and you'll never get a good adjustment b/c you are letting the fuel run out and not allowing the float to do its job.

This is what I do.

Make the adjustment and then crank the car and let it run for a minute so that the new adjustment sets itself then check it - repeat this process until it's set. It's just a trial and error thing and it may take a few go's at it to do the job.

If your plugs are tan, chances are that the jetting is okay. If in fact, you do have 68's and 70's it should run okay with that cam.

Idle air adjustment:
start the engine and idle it up to about 1500rpm. Start on the passenger side and turn the idle screw in until the engine stumbles. Slowly turn it back out until it stumbles. In between these two points where you have screwed it in to make it stumble and out to make it stumble is the sweet spot and you'll just have to use your judgement as to where the engine idles best.

ART

[DartGT66]

The correct way of adjusting the fuel pump is the following; the pump should provide gas through the whole throttle travel, so no air gaps between the pump plunger and the arm:
The first adjustment to check is the clearance between the pump operating
lever and the pump diaphragm cover's arm, at wide open throttle. This
clearance should be around .015". The purpose for this clearance is to
assure that the pump diaphragm is never stretched to its maximum limit
at wide open throttle. This will cause premature pump failure. Once this
clearance has been set take a good look at the pump linkage and work
the throttle. Make sure that the accelerator pump arm is being activated
the moment that the throttle begins to move. This will assure that pump
response will be instantaneous to the movement of the throttle. These
adjustments can be made by turning the accelerator pump adjusting
screw that is located on the accelerator pump arm together with the
pump override spring and lock nut.

[MopART]

DartGT66,

Maybe I can learn soemthing here.....
I have found that when I adjust the pump lever to zero air gap, I get a hesitation off idle to WOT. That's why I adjust it with the .015 slack.

What could give me this hesitiation ?

ART

[DartGT66]

Check the www.holley.com, there are pretty good instructions how to deal with their carbs. I can't tell why your car acts like it does, may be several reasons.

[speedy6963]

Are you using vacume advance? if so make sure its hooked to spark ported vacume source and not full time vacume.

Originally posted by road chicken:
Ok, I need a hand here. I have a 383,750 vac sec holley,( the new ones with no gaskets below the fuel level), on a M1 dual plane. heat risers are blocked off 484/284 mp cam set at 0 deg. Timing is set 10 btdc and idle is @ 900 rpm. The engine at idle, will slowly lose rpm till it stalls. I have to constantly keep bliping the throttle to keep it running. this get real annoying with the 4 speed. Any ideas?? Carb, idle speed/ mixture. If I up the timing or the idle speed much more it starts to get into the advance curve. the car does have a slight hesitation off idle,( presumably do to a small shooter or pump in the accelerator pump. Any help would be appreciated. thanks RC

[road chicken]

Mopart: Checked the floats. Front was too LOW.Rear was right on. Jetting is 78/79. I'm not going to tangle with that since the car is geting 15 mpg with out the vacuum advance hooked up. The Jacobs ignition is doing its job, by the way the plugs look. Didn't have time to set the Idle mix yet. I will do it today.

Dart66: set the pump up like you suggested. It was off just a turn to the tight side.Thanks for the tip on the Holley site. I will check it out.

Speedy: I don't have the distributor curved for the motor yet, so I'm just running on the stock mechanical advance, for now.

Thanks, all of you. I will get a chance to play with it this weekend, and I'll let you know what happens.

[road chicken]

Got it. I talked with another friend. Rejetted the carb 75 square. That took care of the stalling problem. Minior bog, but I'll get that. Thanks

[DartGT66]

What carb do you exactly have? Do you have a power valve or power valves on both the primary and secondary sides? I ask this, because usually the carbs have a power valve in the primary side only; this causes the primary side usually have a considerably smaller jet size than the secondary. Ususally the difference is 8-10 sizes.