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36 Accelerator Pump


Rock10

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1 hour ago, EmTee said:

Wow - I can see where that 90* bend that the tube makes to point up the venturi could be a problem.  It seems crazy the way those tubes bend around to squirt into the venturi, given that more modern carburetors simply shoot a stream of gas at the throttle valve to accomplish the same thing!  If you can't clear the jam, I would seriously consider cutting the tube ahead of the point where it enters the venturi and is just pointing down into the throttle body.  Then fill the empty holes in the venturis with epoxy...

You've missed a detail though. This isn't just the accelerator pump It's also the enrichment fuel from the power valve. That fuel would be added to the fuel from the main jets and come out the main discharge tubes on most other designs. On this one, it apparently comes out the accelerator pump squirters, so they have to mix fuel with air in the venturi about as well as the main discharge tubes do.

 

 

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Well, bad news.

It appears Evapo-rust has a bad effect on whatever these carbs are made of.

After soaking overnight in a 50/50 water mixture on the warm setting, I opened up the pot to see the water was gray.

I pulled the carb out to see it was gray also and had a rough texture and left gray residue on my hand.

I have it soaking in a water/Simple Green solution to hopefully stop the action, but I fear I have damaged the carb.  🤕

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Ouch! Wow. I have soaked zinc, brass, aluminum, etc in it and not had a problem. The maker says it only reacts with Iron oxide, and leaves other metals alone. Up until now, it seemed to be true. Sorry for suggesting it. Keep us posted.

 

 

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Nope…….evapo will not touch or damage anything. It removes oxygen with a synthetic molecule. It’s harmless. You have unstable metal.

 

By 1932 Stromberg had all their pot metal issues fixed. Most likely you carb is suffering from exposure. Having serviced countless Stromberg units I have never seen any issues post 1932.

Edited by edinmass (see edit history)
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49 minutes ago, Bloo said:

Ouch! Wow. I have soaked zinc, brass, aluminum, etc in it and not had a problem. The maker says it only reacts with Iron oxide, and leaves other metals alone. Up until now, it seemed to be true. Sorry for suggesting it. Keep us posted.

 

 

I know. I am surprised.

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13 minutes ago, edinmass said:

Nope…….evapo will not touch or damage anything. It removes oxygen with a synthetic molecule. It’s harmless. You have unstable metal.

 

By 1932 Stromberg had all their pot metal issues fixed. Most likely you carb is suffering from exposure. Having serviced countless Stromberg units I have never seen any issues post 1932.

Everything looked great before. I've soaked it in gasoline and paint thinner and dish soap and water and it looked fine until the overnight in Evapo-rust.

My Simple Green soak didn't appear to be doing anything so I put it back in the gas to soak.

The exterior surface is slightly gritty and the inside leaves a gray residue on your hands like old water pipe.

I'll post pics tomorrow.

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Maybe the Evaporust was reacting with a layer of surface oxidation and as Ed suggested, the gray sludge is 'dead' metal.  I guess what I'm hoping is that the rest of the metal is still OK.  How does it look inside, especially the area in the fuel bowl that would normally be filled with gasoline?  Is that area also rough?

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Evaporust is not an acid. The synthetic compound binds with oxygen……so it converts rust into iron oxide, it can not physically attack anything. Thus it’s safe for paint, brass, aluminum, ect. Whatever is on the carb after heating it I have no clue. Porous and bubbles on the surface of post 1932 Strombergs are usually only found on castings that have been weathered. Any appearance of swelling or pitting usually means the carb is going to continue to deteriorate. Heat cycles and unseated garages will accelerate the failure over time. We have glass beaded them in the past and then treated them with zinc chromate but it’s a very dangerous process and it’s very difficult to get access to it. 

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Here are some pics.

The first is the liquid after the soak. You can see it is separating. There were small particles in the bottom of the pot.

Next is the carb. You can see the rough texture and the change in color. It feels like about 220 grit sandpaper.

All I did was soak it in 50/50 Evapo-Rust and water on the "warm" setting overnight.

IMG_1966.JPG

IMG_1973.JPG

IMG_1974.JPG

Edited by Rock10 (see edit history)
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15 hours ago, edinmass said:

Evaporust is not an acid. The synthetic compound binds with oxygen……so it converts rust into iron oxide, it can not physically attack anything. Thus it’s safe for paint, brass, aluminum, ect. Whatever is on the carb after heating it I have no clue. Porous and bubbles on the surface of post 1932 Strombergs are usually only found on castings that have been weathered. Any appearance of swelling or pitting usually means the carb is going to continue to deteriorate. Heat cycles and unseated garages will accelerate the failure over time. We have glass beaded them in the past and then treated them with zinc chromate but it’s a very dangerous process and it’s very difficult to get access to it. 

I agree. I was concerned about using vinegar so I went with the safe solution.

I'm glad I didn't leave it in for 24 hours like I started to.

The inside surfaces don't seem to be degraded but everything is gray.

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It looks to me as though the Evaporust reacted with oxidation on the surface, which it is designed to do.  If the inside is still smooth it should be OK.  Maybe light glass beading followed by a sealer would restore the appearance/color?

 

The big question: Are the tubes clear?

 

Edited by EmTee (see edit history)
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9 minutes ago, EmTee said:

It looks to me as though the Evaporust reacted with oxidation on the surface, which it is designed to do.  If the inside is still smooth it should be OK.  Maybe light glass beading followed by a sealer would restore the appearance/color?

 

The big question: Are the tubes clear?

 

I guess that's possible, but the outside was smooth and clean, just like the inside and I thought it was safe for all metals.

Good news: one tube is all clear.

The other is not. I don't know how clogged it is. Trying to blow back through it.

I think trying to blow from the well out through the tubes caused my problem and has packed stuff into the smallest part.

Still working on a method to get the job done.

I got a swizzle stick/straw that fits over them nicely and allows a spray tube from carb cleaner to fit in the other end.

But I can't get it on the clogged tube. The end is cut too sharp and bent too tight. It just slices the straw.

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