Don't know the model, it doesn't say, but there are two glass bowl Holleys for Fords (at least that is what is stated) on ebay. I actually wrote the item numbers down this time: 4536613463 & 4536613805.

 

there both older model 1904 Carbs..

 

It looks like the seller somehow posted two listings for the same carb. Either that, or he's got two of the critters. Makes me wish I had a manifold that could accomodate more than one...

 

No, those are definitely two different physical carburetors based on the bore corrosion, although they look like the same model.

 

I think that is what is on my parts truck. I will have to take a look. Anybody have information on how the 1904 carburetors works? The power valve is what worries me. The Holley 7HT I am going to try first has a power valve that vaccuum keeps it deactivated or pulled up. When you give to gas the throttle opens and the vacuum drops the power valve drops and a passge opens up and more gas is let in. I am afraid that with dual carbs the valve will not get pulled up and the valve will run all the time. There is a spring that the vacuum has to overcome. I might have to try and measure the spring force of what is in there and get a weaker spring. I am hoping to measure the manifold vacuum and throttle position before and after the switch to get an idea of how much of a change was made.

 

I checked out the carbs.on the 48 and 52 I mentioned .the 48 had what looked to be 7RT on the bowl.could not find anything on the 52 but ford. ART

 

I think the V8 engines had a two barrel carburetor with a three stud bolt setup to the manifold. The striaght 6 has a single barrel with 2 studs.

 

POWER ENRICHMENT SYSTEM
When high power output is required, a richer mixture must be provided than is required for normal cruising when no great load is placed on the engine. The carburetor provides the added fuel for high power operation by means of the power enrichment system, sometimes called the economizer system. The power enrichment system is actuated by manifold vacuum. Manifold vacuum, which is strongest at the idle when there is no load on the engine, is reduced in proportion to the increase in engine loading. This is due to the fact that, as the load on the engine is increased, the throttle plate must be opened wider to maintain any given speed. Manifold vacuum will be reduced because the restriction offered to the air flow entering the intake manifold by the throttle plate will be lessened as the plate is opened. The strength of the manifold vacuum is thus an accurate indicator of the power demands placed on the engine.. Manifold vacuum acting on the economizer diaphragm actuates the power enrichment system. This vacuum from the lower portion of the throttle bore below the throttle plate is transmitted through the vacuum passage to the vacuum chamber on top of the economizer diaphragm. At idle and normal cruising speeds, the vacuum acting on the economizer diaphragm is strong enough to hold the diaphragm up against the tension of the diaphragm. spring. This raises the economizer diaphragm stem clear of the power valve and the power valve will be held in the closed position by the tension of its spring. The power enrichment system will thus be inoperative in conditions of high manifold vacuum. When high power demands place a greater load on the engine, manifold vacuum is reduced. When the vacuum is reduced below a predetermined point, the diaphragm can no longer overcome the tension of the diaphragm spring and the stem will be forced down. This depresses the pin in the center of the power valve, opening the valve. Fuel from the float chamber will flow into the valve and, passing through a horizontal passage, enter the main well. There it is added to the fuel flow of the main metering system, enriching the mixture for full power. The drilled plug in the passage between the power valve and the main well is a calibrated restriction which meters the flow of fuel through the power enrichment system.

 

Chris,

I assume you found the link for the 1904 carburetor manual that Madathlon posted in this thread https://www.ford-trucks.com/forums/s...d.php?t=357338.

 

I found it that is where I found the reference to the vaccuum enrichment system for the 1904 also. Same setup as the 7HT. Might have to start removing springs turns until the circuit atleast starts to work. I have thought about plugging the circuit up until I get the system tuned. Then if I start to run rich I will know why.

 

Doesn't 286Merc have dual Holley 94's? I know you can run two Holley 94's with both power valves functioning. I printed an articles off Fordbarn's website awhile ago written about him on Holley 94 carb. If you can run dual two barrels on a Flathead you should be able to run two single barrels on a 6 cylinder.

 

From the reading I have done the Holley 94 setups treated the second carburetor as the second set of barrels in a 4 barrel setup. The idle circuit and enrichment circuit were not functional.

 

Thanks for thinking of me it is great to have poeple who are willing to help.

 

A note on the enrichment circuit on the Holley 847 Carburetor. I contacted Vintage Speed and I was told he had various springs already setup he just needs to know how much vacuum I have hot at idle. He also said if I have a good motor that is pulling more that 7.5" of vacuum maybe as low as 5". I should be fine with no changes those are the factory vacuum numbers needed to over come the spring pressure and keep the enrichment circuit turned off. I can get off the shelf from him as low as 2.5" I believe. He also said that dual Holley 847 with the factory setup were common on the old Edmund dual 6 setups and they worked good.