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36 Accelerator Pump


Rock10
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4 hours ago, Rock10 said:

Check valve in the very bottom had some crap on it. I have clean that up. The check ball seems OK.

Is there a separate accelerator pump available.

@Rock10, The accelerator pump cavity is part of the carb casting. Are you asking if the pump plunger is available as a separate part or ???  Normally the plunger is not a separate part.  If you need one either buy the carb kit with one or you are going to have to call and ask. Jon, Carbking, may be able to help you.

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Yes. The pump plunger. It may need replaced. I haven't got the carb back together to test it yet.

I was wondering if it was available by itself. Don't need a whole kit.

Still trying to get the main jets out.

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I think this is right for EE-1, but don't take my word for it without double checking me, I'm not sure.

 

https://www.carburetor-parts.com/stromberg-pump-ap1

 

I was just looking at kits for these, and I don't see any check balls. Before buying anything, I would figure out what it is using for one way valves and check that. I have been in these, but can't remember what they used. It might come to me later. Are there two check balls?

 

I have worked on more Stromberg WW and Carter BBD than I can count, and scrutinizing the accelerator pump was part of my routine. The WW and BBD use 2 check balls. New ones came in the kits, and if they didn't seal, you could put the old ones in and hit them lightly with a pin punch. That reforms the seat. Then put the new balls in . Never re-use any balls you hit with a punch.

 

If the accelerator pump is leather with a spring expander inside, and I think it is on the EE-1, you probably don't need a new plunger. Soak it in automatic transmission fluid overnight and spread the cup a little.

 

On the WWs and BBDs, they would run for literally decades without running over or anything, but to be at their best they needed a kit every 3 years or so, mainly because of the accelerator pump but also to clean the crud out.

 

Bench test it. I can't really recommend gas. If it was going right back on the car to run as soon as it was assembled, and it usually was on the cars I worked on, I would just use water. If not, I'd have to find something like paint thinner that wont corrode the carburetor. Fill the bowl up with the top off (if the check valves can work with the top off, if not you'll have to put the top on) and run the plunger manually. You should get instantaneous squirt action with even the slightest motion once the air is purged. If it wont do it, or it's lazy, and you previously soaked and spread the plunger, it ain't the plunger. Go back and nitpick the check valves until they work properly.

 

 

Edited by Bloo (see edit history)
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The Stromberg EE-1 used a pump inlet check valve, which is an encapsulated ball in a brass plug with a screw slot. These should be contained in any rebuilding kit for the carburetor.

 

The power valve assembly acts as the pump discharge check valve. The power valve can become non-functional due to a fatigue spring, or damage from a novice rebuilder. A new power valve should be contained in a carburetor rebuilding kit, but may not be a component of the cheap Cxxxxxx kits.

 

Causes for failure:

 

(1) use of screwdriver instead of special tool to install power valve damaging the valve.

(2) inlet check valve not functional.

(3) defective accelerator pump (especially if modern neoprene rather than leather).

(4) clogged pump discharge tubes.

 

Jon

Edited by carbking (see edit history)
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I have one check ball valve and one power by pass jet as pictured below.

The ball moves freely in the check valve.

I'm not sure how to test the power jet. The center post moves easily down and springs back up.

The plunger seems OK. it's only been installed for less than a year.

There was some gunk around power jet that I've cleaned out. Haven't tested anything yet.

S131-56.png

9594K-300x300.jpeg

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4 hours ago, carbking said:

The Stromberg EE-1 used a pump inlet check valve, which is an encapsulated ball in a brass plug with a screw slot. These should be contained in any rebuilding kit for the carburetor.

 

The power valve assembly acts as the pump discharge check valve. The power valve can become non-functional due to a fatigue spring, or damage from a novice rebuilder. A new power valve should be contained in a carburetor rebuilding kit, but may not be a component of the cheap Cxxxxxx kits.

 

 

What is the price for a rebuild kit.

I made the slotted screwdriver tool to remove the power valve, but I don't know how it was installed originally.

We are looking to buy a tool to remove the jets.

Edited by Rock10 (see edit history)
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Wet test it on the bench like I was talking about. Those flow one direction. Whichever one is sucking back and forth is the one that is not working. If it works correctly... well.... it works correctly.

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I can't get any fuel to pump out.

Where is it supposed to discharge?

I took the power valve out and it still won't pump.

Could the passage be clogged. Is the plunger on the power valve supposed to go down below the slot?

This worked before.

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I cant remember. @carbking will know. The basic plan is the power valve is sealed (closed) and when the plunger goes up, gas is drawn in through the ball valve. Is it filling up? Then when the plunger goes down, pressure blows the ball shut hard, and it blows open the power valve, using it as a check valve.

 

Normally a power valve, including similar looking ones in newer Strombergs, would just be a passage for extra fuel into the main discharge tubes, bypassing the main jets. How they keep the accelerator pump discharge separate in this type is what I can't remember. Maybe they don't keep it separate? Maybe it just blows out the main discharge tubes? On some level that makes sense I guess. The whole reason for an accelerator pump's existence is that the air weighs less than the gas, and so it accelerates faster than the gas. Maybe rather than spraying gas to cover the inevitable ball of unmixed air that gets in, they just mechanically accelerated the gas(?!).

 

If that's the case the gas should be blowing out the main discharge tubes, I guess, minus a little bit that probably leaked backwards through the main jets. You should be able to suss out where the passages go by blowing brake cleaner through them. Don't squirt yourself in the eye. It's easy to do.

 

I have some Stromberg 97s around here that have the power valve in the bottom of the accelerator pump like that. If I could find them I would look.

 

 

Edited by Bloo (see edit history)
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Too late on the eyes. 🤕

I did try to shoot some in. I can't see it coming out anywhere.

When I blow air into the bottom of the pump well, it doesn't seem to come out anywhere in the carb throat.

There are small copper tubes curling around the venturis on the outside. I think those are supposed to be the discharge tubes, but nothing comes out.

Like I said, this worked fine before. Don't know what happened.

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8 hours ago, Rock10 said:

There are small copper tubes curling around the venturis on the outside

Correct, that`s them. I`ve always used Berrymans Chem-Dip, and their Carb Cleaner to squirt into all passages to make sure they are clean. Some carb kits have extra gaskets with holes in different locations, wrong gasket could block a passage.BERR0120C_1_x-large.jpgBerryman B-9 Chem Dip Parts Cleaner with Basket - 96 oz.

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No gaskets right now. Just the bowl section of the carb sitting in a pan.

Again, this was working fine. The car has set a few weeks between running from time to time. Not sure when the problem actually started.

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3 hours ago, Rock10 said:

Are those tubes removable?

Rock, i have an all new `36 233 engine on a stand with a Stromberg on it, that i rebuilt(few years ago, never been fired up). I`m tempted to remove it and take it apart just to refresh my memory, on if the squirt tubes are removable, or spot anything that might be causing your problem.

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Rock, i`ve got mine off the engine and top removed. I`m not so sure the squirt tubes are removable. I put the carb in a pan and filled the fuel bowl with gasoline, then took the pump plunger, put it in the hole, and manually pushed it downward, first plunge, fuel squirted thru the nozzels, next push, no squirt, several times push, no squirt. So i got to looking, there is a vertical slot in the side of the pump well, the pump has to be raised high enough in the well, above the bottom of the slot, to let fuel gravity fill the well for the next plunge of the pump. Once i raised the plunger high enough, it squirts on every pump. You may not be raising the pump high enough to let the well refill during your pump test. Try it again, raise the pump a little higher in the well, then see if it`ll squirt on every pump. No check balls that i can find.

Edited by pont35cpe (see edit history)
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If that is the case, how can the power valve work?

 

When acting as a power valve, it just adds fuel that does not go through the main jet. If the fuel is going out the power valve, again not as an accelerator pump function but as a power valve, the fuel would have to be getting in to the plunger area somehow. Since the power valve is mechanical on these, triggered by the plunger, you could not depend on that slot. The plunger would be all the way down pushing the power valve open.

 

As for the discharge tubes, and the main jets as well for that matter, I wouldn't be taking that stuff out anyway if I could help it. It is just too easy to damage.

 

 

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The pump and power valve are meant to cover short time periods. In normal operation while changing engine speeds, the pump would move very little and squirt the necessary fuel allowing the well to refill when you lifted your foot. In a WOT situation, the plunger pushes all the way down on the power valve allowing a big shot of fuel to pass into the carb until the jets catch up.

This is my simple understanding.

I will try again with the float bowl full.

Thanks pont35cpe

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A "normal" power valve opens under low vacuum. When is vacuum low? When your foot is down hard. This one just trips the valve mechanically instead. Is that better? Worse? I don't know. I do know it needs a constant supply of fuel. Engines want a richer mixture at full power than they do at part throttle cruise. This is not a transient thing. It needs to stay enriched as long as your foot is in it.

 

The accelerator pump is transient. That's different. It gives a squirt.

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It is time to have a good look at this thing.

 

S131-56.png.5db02a9d06c390c7dd3037722cc1

I don't like this design much. They were trouble, and in newer designs both Stromberg and Carter had eliminated them in favor of loose ball bearings seated by gravity. Then, since the ball was loose, if the seat would not seal you could just hit the old ball with a pin punch, restoring the seat, and then put a new ball in. With the ball and seat encased in brass like this, the best you can do is clean it out and hope it seats ok. If not you have to put in a new assembly and hope it works better. Good luck. Sometimes they work, sometimes they don't.

 

Without being able to see this carb, but based on what we have seen in this thread, there is a problem with this thing. Blow through it. Blow through it the other way. It needs to seal one way. My guess is this thing is located in the bottom of the fuel bowl,and just leaks fuel through a passage into the bottom of the accelerator pump cylinder, but above the power valve. Is that about right? That way it could just supply fuel to the power valve under static conditions, but when the plunger comes down, the fuel would blow backwards and seat the ball. Unless the ball didn't seat of course. Then it would blow the fuel back into the bowl.

 

I'd blow through the power valve both ways too. It also needs to seal.

 

Edited by Bloo (see edit history)
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It is in the bottom of the bowl. It lets fuel in and then blocks the back flow when the pump is working.

I've checked the check ball. It is working OK.

I think you have it right on the power valve. It stays open as long as your foot's down.

I think I have a blockage in the passages going to the carb throat from the pump cavity, but I need to try pont35cpe's suggestion first.

I'm not getting the little squirt you need when you give it a little gas.

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27 minutes ago, Bloo said:

What happens if you blow carb cleaner into a main discharge tube with the power valve removed? Does it show up down below where the power valve is supposed to be?

 

There is a well below the power valve that should always hold fuel.

There appear to be 2 holes in the thread area that probably lead to the discharge tube for the pump. I can't get a good look at those or get anything in them due to the small space. When I plug the well with a paper towel wrapped around a piece of vacuum hose I can blow down into the threaded area. The air should come out the discharge tubes. It doesn't.

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29 minutes ago, pont35cpe said:

Well my theory is wrong. I noticed when reassembly, the pump plunger at it highest, with the top in place, is still below the slot. Nothing left in the pump/squirt circuit except the problematic jet Bloo mentions.

Well that's a test I won't have to do.

The little check ball in the bottom is working OK. When I blow in the well, nothing comes out in the float bowl.

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What happens if you put carb clean in a main discharge tube from the venturi end? Where does it come out?

 

EDIT: Never mind. I just found some EE drawings. Apparently it leaks the extra power valve fuel out of the accelerator pump nozzle, with no connection to the main circuit.

 

If it isn't blowing fuel backwards through the check valve when you pump, where *is* it going? It must be going somewhere, or it would just block you, hydraulically lock, and not let you move the piston.

 

There might be a way to put compressed air on the nozzle. In one of these drawings, there is a plug straight up into the bottom of the casting that leads to the passage of interest. If the plug is there, you would have to have the check valve in place (preferably with a drop of oil), and the power valve in place, and the plunger in place, which would have to be held in VERY solidly. You could put air in that plug and have it blow out the nozzle..... I think.

 

 

Edited by Bloo (see edit history)
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# 28 is working OK.

#29 is questionable but not in the carb right now.

#30 and #31 seem to be my problem. And I see no way of checking/cleaning that passage.

As you can see, when the plunger goes down there should be nothing stopping the gas from coming out.

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 Would it be possible to get a little tube over the end of 31 from the outside? It would probably be better to blast backwards with brake or carb cleaner if you can figure out how. If you cant, maybe soak it in carb cleaner (dunk it) for a couple days and try to blow the nozzle out with compressed air. If you removed the power valve and introduced compressed air in that hole (with a rubber tip), would that pressurize the nozzle? it looks like it would from the diagram.

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No, #31 is right up against the venturi.

I might have to buy a bucket of carb cleaner and let it soak.

The power valve is out and I've tried to pack the well a blow compressed air in. It just blows the packing out.

I wouldn't think there would be any major constriction there so I guess it must be clogged with something.

There was some grainy like substance around the power valve and in the well when I took it apart.

The car had sat for 3-4 weeks this summer while we changed the torque ball seal. I wonder if there was water in the carb that evaporated and left the crud.

I don't know.

Edited by Rock10 (see edit history)
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The pump discharge tubes CAN be removed, but you have maybe a 90 % probability of ruining the tubes in removal; so ......................last resort only.

 

DO NOT GET TRICKED INTO BUYING THE REPROS AVAILABLE FOR THE EE-1 FORD CARBS, AS THEY ARE NOT INTERCHANGEABLE WITH BUICK.

 

More than likely, there is a clog of fuel residue in each tube. The I.D. of the tube is roughly a number 60 drill, pretty small.

 

Jon

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