Hah so just buy a plug and it and that's it?

 

Yes.

/David

 

http://youtu.be/1dZDLkiUnQM
Hey David listen at :05 you can hear when he gets into the secondaries and it gets fat

 

#ad

Looks blocked off from the factory.

 

Did seem a little dirty so I cleaned it up but other than that it seems fine. I did try Revving just the secondaries like I saw on a video but still, doesn't go that rich. Maybe some dirt in the needle and seat I really don't know. Should I just down the jets?

 

I think you should try smaller jets in the secondarys and see if it makes any difference. You have vent tube extensions? Just be careful, let go when/if it leans out.

/David

 

I do have vent tube extensions #ad

 

I don´t know if it makes any difference, but my vent tube extensions are not as long. I also think that i´ts not recommended to have the carb hat pointing 9 or 3 o´clock. 12 or 6 o´clock seems more appropriate. But the easiest test is to jet it down on the secondarys.
Hope it works!

/David

 

How long are your vent tubes

 

Ok so got the nitrophyl floats to work, I had to sand then down on the side a bit because they seemed to stick and I also did the bending of that wire like David said, they work. My grandpa wanted me to use his plug scope and check the plugs and non seems out of satisfactory but it still goes rich, even if you just rev it out of gear. Still just need to lower jets or does this sound like anything dofferent

 

Nice to hear that you finally got them to work! Just Try and jet it down and see what happens. Your getting there!

/David

 

Something that seemed so simple affects so much.

 

This thing is seriously a pain lol it runs fine and holds say- 2000 rpm fine without the carb hat, you put that on and try doing the same thing- 2000 rpm- it starts losing rpm and starts going rich and dies. Take that off and it's fine. Any ideas?

 

I said rich but it goes lean. I'm going brain dead hah. I seriously don't know what more to do. You fix one thing and another thing appears. Hah. Any ideas help.

 

Thats part of tuning, you can try enlarging the ifr's they still are feeding engine at 2k. You will have to readjust idle screws after changing the ifr's.

 

I just can't understand why it suddenly changes when the cold side is all connected

 

More air means leaner.

 

Do you think it's possible the fuel bowls are being over pressured from the vent tubes causing the needles to seat and the bowls run dry?

 

No, fuel pressure rises with pressure from hat going to regulator. So fuel pressure should always be higher.

 

Relocating the Holley Idle Jet

In the original Holley carbs the idle feed was located at the bottom and for good reason. NACA paper 49 states in one of the conclusions: "Submerged metering passages are free from instability and irregularity of discharge when the head is very small". What this mean is that on a performance engine with low idle vacuum the idle characteristics will be improved with the idle feed in the lower position. Because the idle circuit can impact the the air bled into the mainwell at high speeds, it may be that someone in the past saw an improvement on a specific engine at high speeds by moving the idle feed up, however with the advent of metering blocks with more emulsion holes to chose from making changes to the main metering does not have to be done by manipulating the idle feed. This was also done without regard to how it affects the idle and transition metering, both are improved significantly when moving the idle feed back to the original location.

The tools needed are a 6-32 bottoming tap, and 1-60 and 61-80 drill indexes. Spiral flute taps cut much easier if you can get them. 6-32 brass set screws are needed, I prefer to use 1/8" long for the idle jet however 3/16" can be used. The pictures show the relocated location and how deep to thread them. I use a couple 6-32 nuts to make a stop to get the depth correct so the screw is flush with the bottom of the slot. Take your time, use lube on the tap.

Locating the Idle Jet below float level is more important than many people realize because cruising at a low RPM and steady speed the fuel delivery is nearly 100% through the idle circuit (T-slot), and with the jet above float level the AFR oscillates a lot, as much as 2 AFR or more. Smooth idle, clean sparkplugs and oil, and good fuel economy, all depend on a consistent idle-low speed circuit.

An un-damped vacuum gauge will clearly show engine manifold pressure (vacuum) oscillates constantly and as valve timing becomes more radical the increased overlap causes larger pressure swings and more intense oscillation.

An un-damped gauge clearly shows engines are not a steady flow device. The intake pressure (vacuum) is oscillating with each intake suction stroke and overlap reversion pulse. Because passages and cavities in carbs and manifolds have individual resonances at particular frequencies, the resultant effects are more pronounced at some engine speeds than others. Because air is compressible, it is elastic, it can rebound like a spring and as a result it bounces and reverses direction in small passages in carbs.

With a high (above float level) idle jet, air can easily get upstream behind the jet when the idle fuel is pushed backwards by the pulsing.

When the jet is submerged, the air cannot get back upstream of it as easily because the much greater viscosity of the liquid fuel (than air) on both sides of the jet impedes the backflow and the air cannot get back through the jet unless the flow is reversed for a longer period of time than the frequency of the pulsations.

Another undesirable phenomenon caused by the high idle jet is the larger oscillations in the idle circuit causes a pumping effect on the main well that results in the booster nozzle dripping in spurts and blobs before it would normally start to flow if the venturi air flow were the only excitation and the idle circuit flow was more regular. With a submerged jet the metering reversion isn’t as severe or does not occur at all unless the pressure reverses for a longer time period than the manifold pressure (vacuum) pulses at a cruise.

This submerged idle jet phenomena was thoroughly studied and well understood 95 years ago during aircraft carburetor research for World War One.