Size of Holley Vaporizer Jet

[OilyBill]

Does anyone know the specific size (Drill bit or decimal size) for the Holley Vaporizer Jet orifice or Spray bar. This is the part that screws into the main fuel feed, just above the screw attachment for the float bowl.

I have a Holley Vaporizer I just disassembled, and it was packed with carbon dust, all through the vaporizer assembly and up the tube. I assume it is running EXTREMELY rich. I installed a brand new jet when I overhauled the carb, but my assumption is it may be that the orifice hole is just way too large. The engine runs OK. Anyone have an actual dimension or drill bit size for this hole, so I can check the orifice I installed?
Thanks very much!

[OilyBill]

This would be item 6286 on the Vowell Art drawing of the Vaporizer carb assembly,

[Scott_Conger]

William

if you replaced #6286 with new, it's correct

it is the spray nozzle and is not a jet

if the carb was running rich, then that is due 100% on the condition of the adjusting needle and the adjusting needle seat as well as where the operator left the needle/richness setting

if your car is now running well, then that's pretty much it

with the amount of carbon you're describing, it sounds as if in another life there was considerable timing problems and/or backfiring going on.

[OilyBill]

The carb has been completely disassembled, cleaned, de-rusted, and all worn or damaged parts replaced with new.
My assumption was the adjustment needle (Dash Adjustment) can only RICHEN the mixture.
I understood that the 6286 orifice is fixed, has no adjustment, and all that can be done is to richen the mixture with the dash adjustment if the engine is knocking or on a heavy pull.
Can the dash adjustment be used to lean the fuel mixture that goes through the 6286 orifice? What is the procedure for this? It may be my false assumption that the mixture is fixed at all times to the FORD engineered level, and the only variation is through the air damper that adjusts itself based on throttle opening to increase or decrease total mixture supplied.
My problem is that both the owner and myself thought we had the dash adjustment turned closed, and therefore we have a problem with excessive richness, depositing all the carbon soot in the carb.
I think I may be missing something here. I checked the orifice size in the 6286 insert, and it is .0625, or 1/16th of an inch in diameter. The part is brand new.
If this is the entire cause of the rich running condition, I can easily make another 6286 insert, with a diameter of .050" or .055" to reduce the rich mixture to a more economical and less soot producing level.

[Chris Barker]

I believe that the 6286 has minimal effect on the mixture; that is entirely governed by the needle valve and its jet. If you were to screw it right in, no fuel would reach the engine.

[OilyBill]

No, there is an 1/8" slot across the bottom of the fuel inlet, just where the carb bowl mounts. So fuel flows freely from the carb bowl up the orifice without any restriction. My assumption is the mixture adjustment is only to ADD additional fuel if the car is working hard or knocking, or to add fuel to make cold starting easier. But that dash adjustment has no effect on the regular gas supply from the carb bowl to the carb inlet with the 6286 jet. My problem is this carb seems to be running exceptionally rich.

[slang250]

Hello William,

You might have a Holley NH bowl nut instead of the Vaporizer one in your carburetor.

The slots at the bottom of the bowl should only lead to the drain valve and not to the spray nozzle in the Vaporizer.

The nut that holds the bowl on should not have a drilled hole in it that leads to the spray nozzle in vaporizer but does in the NH.

Here is a photo of the vaporizer one without the thru hole I'm talking about.

When the correct nut is installed all gas regulated by the adjusting needle. With the wrong nut installed the gas can bypass it from the bottom and will always run to rich.

[Scott_Conger]

William

first, it sounds like someone who did not know how Vaporizers work has altered it irreparably, and second, Steve Lang mentions a very important point which I frankly should have caught, and is a part which is often mistakenly installed as the wrong part. It is a common error when buying parts that "look the same" as what came out.

any fuel that can get to the nozzle other than past the needle and jet whether due to a groove being cut in the bottom of the bowl stem, or the wrong bowl fitting like Steve mentioned will cause the carb to run entirely without regulation. It would be a wonder that it operated at all, quite frankly.

[OilyBill]

Thanks for the input, folks! I appreciate it.

No, it has the correct Vaporizer bowl securing nut. There is no hole in it. It was a new part ordered from Snyders due to the old one being not only rusty, but all hacked up. All the gaskets and seals are also brand new and freshly installed.

So my mystery now is how is all the fuel getting past that bowl securing nut, and into the mixture area?

Is the dash adjustment the ONLY source of liquid gas to get into the actual carb circuits? So if I close it all the way, the engine should shut down due to no fuel supply, is that correct?

The problem there is that they tell you to open it slightly for starting, and then when the engine starts, to close it completely. So if that is the case, where is the engine getting it's fuel from, other than around the slots in the end of the bowl mount staff, that gets the bowl retaining nut and drain valve installed in it?

I am mightily puzzled!

I really DON'T want to switch to a different carb. This carb is the one that was on the car when we restored it, and I have heard from many people that the Vaporizer carb works very well, and they only time they have a problem is if someone screws with the carb, or does not rebuild it properly. I did my best to insure that every assembly on the carb was clean, correct, and operable. (Such as the air regulator weight assembly. I found out that the new pin and retainer screws would jam the weight assembly if tightened all the way down, due to the tiny center hole section that engages the weight support shaft, actually being too long and the end of the mounting screw supports would move down the weight shaft until they contacted the weight body, locking it in position. I remachined them to give some clearance so the air weight would swing freely with the screws tightened down.) Each part of the carb assembly was put together and tested, and as far as I know is correct. This carb is authentic to the vehicle. Ford built millions of cars with this exact same carb on it, and they drove like new cars do. So I just need to find out what is wrong and creating this problem.
My conundrum is, what is the normal source of fuel supply for this carb?. If it is the dash adjustment, then why doesn't the engine shut off when this is screwed closed per the Ford Owner's Manual. Is it correct that there should be NO fuel flow if this is closed?

If the dash adjustment is NOT the primary source of fuel, then where is the fuel to come from when the dash adjustment is screwed closed all the way? My assumption is it was the slots in the bottom of the mount staff where the bowl attach nut and drain go, but perhaps I am wrong on that as well?

[OilyBill]

Thanks for the input, folks! I appreciate it.

No, it has the correct Vaporizer bowl securing nut. There is no hole in it. It was a new part ordered from Snyders due to the old one being not only rusty, but all hacked up. All the gaskets and seals are also brand new and freshly installed.

So my mystery now is how is all the fuel getting past that bowl securing nut, and into the mixture area?

Is the dash adjustment the ONLY source of liquid gas to get into the actual carb circuits? So if I close it all the way, the engine should shut down due to no fuel supply, is that correct?

The problem there is that they tell you to open it slightly for starting, and then when the engine starts, to close it completely. So if that is the case, where is the engine getting it's fuel from, other than around the slots in the end of the bowl mount staff, that gets the bowl retaining nut and drain valve installed in it?

I am mightily puzzled!

I really DON'T want to switch to a different carb. This carb is the one that was on the car when we restored it, and I have heard from many people that the Vaporizer carb works very well, and they only time they have a problem is if someone screws with the carb, or does not rebuild it properly. I did my best to insure that every assembly on the carb was clean, correct, and operable. (Such as the air regulator weight assembly. I found out that the new pin and retainer screws would jam the weight assembly if tightened all the way down, due to the tiny center hole section that engages the weight support shaft, actually being too long and the end of the mounting screw supports would move down the weight shaft until they contacted the weight body, locking it in position. I remachined them to give some clearance so the air weight would swing freely with the screws tightened down.) Each part of the carb assembly was put together and tested, and as far as I know is correct. This carb is authentic to the vehicle. Ford built millions of cars with this exact same carb on it, and they drove like new cars do. So I just need to find out what is wrong and creating this problem.
My conundrum is, what is the normal source of fuel supply for this carb?. If it is the dash adjustment, then why doesn't the engine shut off when this is screwed closed per the Ford Owner's Manual. Is it correct that there should be NO fuel flow if this is closed?

If the dash adjustment is NOT the primary source of fuel, then where is the fuel to come from when the dash adjustment is screwed closed all the way? My assumption is it was the slots in the bottom of the mount staff where the bowl attach nut and drain go, but perhaps I am wrong on that as well?

[Scott_Conger]

you mentioned the slots in the bowl mounting/casting. I said that is where the fuel is going to the nozzle in an unrestricted fashion. If I am not misunderstanding you, THAT is where the fuel is coming from.

there should be NO slot on the very bottom of that member, and there should in fact be a seal on that face/bowl interface

see: https://mtfca.com/phpBB3/app.php/gallery/image/637

Who is "THEY" who tell you to screw the mixture adjustment closed for normal running?

My assumption is it was the slots in the bottom of the mount staff where the bowl attach nut and drain go, but perhaps I am wrong on that as well?

...again, those slots do not belong there...it sounds as though someone has ruined your carburetor out of ignorance of its operation. Those slots show up in later NH carburetors, whose mixture function is entirely different and perhaps some goof felt the factory left them out of your carburetor and it needed them...if so, too bad.

The threads on the plug may slow the flow of the gas, being a tortured path, but the fuel will still find it's way up in an uncontrolled fashion.

[speedytinc]

Does anyone know the specific size (Drill bit or decimal size) for the Holley Vaporizer Jet orifice or Spray bar. This is the part that screws into the main fuel feed, just above the screw attachment for the float bowl.

I have a Holley Vaporizer I just disassembled, and it was packed with carbon dust, all through the vaporizer assembly and up the tube. I assume it is running EXTREMELY rich. I installed a brand new jet when I overhauled the carb, but my assumption is it may be that the orifice hole is just way too large. The engine runs OK. Anyone have an actual dimension or drill bit size for this hole, so I can check the orifice I installed?
Thanks very much!

Thursday T party, we dissected the function of the vaporizer with actual parts in hand & consultation from smarter guys than I.

The jet(small brass,down in the base of the carb stem.) is .062 as is the jet that goes up thru the center. This small, removable jet IS to large & is regulated down by the needle adjustment. The same jet/spray bar as is used in an NH is there as an unregulated pass thru passage.

If you can adjust down the needle(regulate the fuel quantity) to where you can lean out & kill the motor, the system is working correctly.
If you can turn the needle down to seat & the motor still runs, you have a leak in the system & are sucking extra un regulated fuel.
A big mistake would be having a regular NH drain valve. The top of the drain valve must be closed off or you are sucking a lot of unregulated fuel.(very rich)
See Langs post.
You claim to have the correct drain.

I must respectfully disagree with the incorrectness of the 2 slots in the casting @ the bowl contact. They are there for fuel/water/other junk to drain out of the very bottom of the bowl. They are the same slots that serve the same purpose on a NH. These slots do not create a path for unregulated fuel in the vaporizer unless the wrong drain valve body is used. Being that there is a half thimbles worth of fuel captured in the stem above the sealed off drain valve top that doesnt drain, junk etc is captured & can only leave up the unregulated spray bar orifice or back thru the brass functional jet. Therefore, a complete draining would require a removal of the drain plug valve body. The same condition exists in early side drain NH's (pre 23ish) that do not have the drain slits @ the bottom of the stem.

Other sources of unregulated fuel could be a crack in the body stem. Someone could have drilled a hole in the stem to match a NH thinking it improves fuel pick up.
Do make sure the needle will seat in the jet all the way to shut off regulated fuel flow. If not seating, The needle could be too short from too many tip re facings or burs from screwdriver knackering on the jet. You can remove the bowl & visually see the point of needle & seat @ the jet.

As with a NH, once the proper fuel level is set for both idle & hi speed functions, There is no more need to constantly fiddle with the carb adjustment unless there is a large altitude change.

There should be no need to richen the needle for starting. Especially on a vaporizer.
Functionally, There is that half thimble area in the stem base that fills up with fuel up to the bowl fuel level until running, This fuel is now unregulated coming into the motor thru the .062 orifice of the "redundant" spray bar. (like unscrewing the adjusting needle out a full turn.) Once this pocket of fuel is exhausted, the brass jet takes over to regulate the proper fuel flow for running.

I hope this solves your problem.

[Scott_Conger]

John

thank you for investigating what I clearly should have myself...

and to Bill, I apologize for giving incorrect information. It has been quite awhile since I've worked on one, and humbly submit that they are not my forte. If John says those grooves are there, then they are there. Still, if the carb will not regulate via the needle and jet, there is a fuel leak somewhere in that circuit...I will not try to speculate from here. I usually stick to topics for which I have plenty of recent experience, and this lapse let me put my foot in it big time.

[speedytinc]

The carb has been completely disassembled, cleaned, de-rusted, and all worn or damaged parts replaced with new.
My assumption was the adjustment needle (Dash Adjustment) can only RICHEN the mixture.
I understood that the 6286 orifice is fixed, has no adjustment, and all that can be done is to richen the mixture with the dash adjustment if the engine is knocking or on a heavy pull.
Can the dash adjustment be used to lean the fuel mixture that goes through the 6286 orifice? What is the procedure for this? It may be my false assumption that the mixture is fixed at all times to the FORD engineered level, and the only variation is through the air damper that adjusts itself based on throttle opening to increase or decrease total mixture supplied.
My problem is that both the owner and myself thought we had the dash adjustment turned closed, and therefore we have a problem with excessive richness, depositing all the carbon soot in the carb.
I think I may be missing something here. I checked the orifice size in the 6286 insert, and it is .0625, or 1/16th of an inch in diameter. The part is brand new.
If this is the entire cause of the rich running condition, I can easily make another 6286 insert, with a diameter of .050" or .055" to reduce the rich mixture to a more economical and less soot producing level.

6286 is the same spray nozzle/jet as used in the NH. AKA 6214B (interchangeable according to Chaffins catalog.)In the NH, the mixture needle partially obstructs the opening to regulate the precise amount of fuel.
In a vaporizer the fuel mixture volume is not regulated here. Fuel flows in a very rich mixture until the chamber under this jet is used up & the fuel is then precisely regulated thru another jet. This creates a rich mixture for starting. (6283) also .062 orificed, but regulated down by the mixture adjusting needle. (the same way fuel mixture is regulated in a NH thru 6286/6214B)
The fuel to run the motor is dependent on regulated fuel thru this separate jet. As with a NH, closing the needle adjuster down to a complete seat closes off fuel & the motor will die. If the motor doesnt die, you are getting extra unregulated fuel thru a defect in the circuit or your needle is not seating fully.. If the motor will still run with a "normal" setting, it would run rich. Make sure the needle will go in all the way to completely block this jet orifice.
Changing the orifice in 6286 would only mess the system up further.

[OilyBill]

Thanks to Scott C, John K, Steve L, and Chris B for your contributions to this post! It is all the varied experiences and knowledge that make this forum so valuable. The discussion revealed several points I needed to verify to insure the carb was set up properly, some of which I was unaware of previously.
I learn something new every day!

My step A is: Get another Vaporizer center casting, rebuild it, reassemble the carb, and see if there is any change.

Step B. If there is still no good result, then the next thing is to find a different carb, set the Vaporizer aside for now, and deal with it later. I want to get a carb on the car that will work. I have spent several months on this stumbling block, and I need to end it and move forward. I am still committed to the Vaporizer carb, but it will have to be delayed until I have time to mess with it on the side. The guy I am restoring the car for needs to get on the road, get the bands adjusted, and get used to driving the car. I need to get it out of the garage and under way so he can do that. Standing around in a garage, watching a Model T idle, is just wasting time and not productive.

So. like I said, the next thing is to make one final attempt with a new center Vaporizer casting, and then if there is no positive result, move on to a different carb, so the car can be driven.

The next question becomes, what would be a good, appropriate and reliable carb to use in place of the Vaporizer?

[RajoRacer]

I'd say a Holley NH - quite a simple carburetor.

[Corey Walker]

On an NH the fuel flows freely through a hole in the casting directly below the spray nozzle into that cavity and the spray needle regulates how much gas can come out of the top of the nozzle to mix with air. A leaking, nonexistent or a new gasket stacked on an overlooked old gasket can cause gas to leak past and the spray needle won’t be able to meter the gas because it has 2 paths to follow.
The same hole is there on the vaporizer but the fuel flowing into this hole is regulated by the fuel adjustment needle which meters the amount of gasoline flowing into the cavity under the spray nozzle so even if the gasket there is bad, only a certain amount of fuel should be allowed in and screwing the needle all the way in should shut off the fuel coming from inside the bowl and it should die.
It seems like there would have to be a hairline crack in the body or the threads not sealing well where the nut screws in. If the threads were that bad it would more than likely strip before it tightened sufficiently. Those 2 slots in the bottom are for fuel to flow to the drain and started with the center drain NH’s.

[OilyBill]

Thank you, Steve and Corey!

The Vaporizer is undergoing reassembly now. I will not be able to try it out until November 13th. So then I guess I will have an answer on the Vaporizer.

I will start looking for a Holley NH. What is a decent price to pay for a restorable unit?