Leaky new needle & seats? And how do you lean out idle a/f?

So I rework my Holley 4150 and bought brand new stuff.


It has vitton .130 needle and seats... But the problem is I can't set the float on the secondary. The primary is set. It would trickle over the view hole with engine running.

The secondary keeps on over flowing. I have tried to tighten it clockwise and it still over flows. When I turn it counter clockwise it leaks at the adjuster. Any pointer?

The next is my idle a/f. It's around 10.5 to 11

I set the timing at 24* locked and vacuum is dead set at 22 which is highest/best I could set it using the idle mixture.

The car idles great but too rich. I thought that the primary does not affect idle a/f?



Set up is a 302 mustang with Holley 650
Jet is 72/90

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

you can get idle quality from the pri/sec if 4 corner idle screws-its normal for the set screw to leak when adjusting the float level, you kind of have to chase the nut with the screw when adjusting-if you havent already, get nylon washers for the float adjustment screws
sounds like dirt in the sec n/s, .130 is huge and doesnt take much to leak by them

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Thanks for the response

No four corner just in the primary. And I have moved it out and in, it is simple rich no matter how much I screw it in or out.

Brent suggested messing with the idle-air bleed...so I'll be looking that up right now and see what I need to do. For some reason I must have missed this from the hanger instruction or it was not in there.

I took out the needle and seats clean even sprayed compressed air. Still filling up.

What else could cause the n/s to not close?

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Take the bowl off and blow through the inlet with your mouth , lifting up and down on the float . If its not sealing , look at it further til you find out whats keeping it from doing so .

If it is sealing , then look into things that might be interfering with the float , like jet extensions .

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Thanks I will do that.

Odd cuase the jet extension and the float was a package thing.

I'll find out in a few hours onc I rip her apart again.

Question where is the idle air bleed? And what size do you think I should drill it to? My idle a/f is at 10.5 no matter how much I mess with the idle mixture screw.

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Dont do anything to the bleeds until you figure out the float issue .

But for reference , they are the outer bleeds .

#ad

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

I took out the bowl and checked it. Everything looked good so I put it back and then i guEss that fixed it cause now it worked perfect.

Now it idles at 11.5

How much do you think I should drill the idle air bleed?

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Is your transfer slot/throttle blade set right?

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

Hmm I don't know. I wasn't aware of that. I will check it tomorow. How do you adjust this?

 

Re: Leaky new needle & seats? And how do you lean out idle a/f?

The Tslot should be exposed slightly as shown. Not having any showing will cause a stumble as you apply the gas from it going lean. Having too much exposed will feed enough fuel to the engine at idle, to make adjusting the idle air fuel screws not have any effect, making it idle too rich. It is best to set the Tslot so the opening that is exposed is as long as it is wide, square. After doing this, make your idle speed adjustment using the secondary idle adjustment screw. If you are running a real radical cam, this may not be enough to control the idle. If that is the case, drilling small holes in the throttle blades may be required to provide enough air to the engine, while the blades are nearly closed. On some older carbs you may have to remove the secondary adjuster screw from the bottom of the base plate and put it in from the top to allow easy access. The Tslot controls the fuel delivery until between 2200 and 2800 rpms in most engines when the fuel starts feeding from the boosters. If you are rich or lean before that, it is most likely from a idle air adjustment, Tslot, or emulsion circuit that feeds the Tslot causing the problem.