bought a mystery 850 double pumper...

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Inner diameter of booster...
IMG_20170614_201133.jpg
 
inner diameters are ..... whats the butterfly size? That is the difference between the 2. I got a 4781 850 downleg with 1 3/4 bores.

---disregard, I just saw your NSK mic shot of the 1.7465 bores. thats close enough !--- I was looking at metric side and was like wtf?
 
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If its the 850 it should work well on a 408 w/ W2s and solid roller pushing a 4 sp...... Right?
 
mbaird said:
If its the 850 it should work well on a 408 w/ W2s and solid roller pushing a 4 sp...... Right?
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IDK. I only worked with the 830. And it was worthless. Like I said, I couldn't find a professional carb builder who would touch it.

When I take it out to the range to shred it, I'll take a video.
 
A carburetor is nothing more than a controlled fuel leak. If you understand how it works you can tune it, Do some home work!
 
mbaird said:
Wow.... Such anger.... Bad day?
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There wasn't any anger, I was just stating a fact that a carburetor is nothing more than a fuel leak that is controlled.

When I worked for a car dealer if we had a car that the fuel pump was bad instead of pushing it through the parking lot to the bay we would spray carb cleaner in the throttle body, one guy sits on the engine spraying the carb cleaner the other driving the car into the shop.

Like I said if you understand it you can make it work by changing a jet, making the hole bigger or smaller, drilling the metering block, or plugging a hole, and so on.
And I am having a great day, thanks!
 
brian6pac said:
A carburetor is nothing more than a controlled fuel leak. If you understand how it works you can tune it, Do some home work!
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I guess I should have sent the piece of **** to you. When Dave Braswell, Dale Cubic and BLP tell you it's not worth bothering with, I took their advise. Maybe you should go to work for one of them. Evidently you can fix what they won't even work on.
 
So what was the problem you were having ? Too lean on the middle and to fat at WOT, Wont Idle?
 
brian6pac said:
So what was the problem you were having ? Too lean on the middle and to fat at WOT, Wont Idle?
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Transition from cruise to WOT. It would go dead lean. The first fix was a down leg booster. That helped. It actually moved the lean spot up the RPM curve.

Then I put the 850 base plate on it and that made the hole smaller.

Then we decided to use Tslot restricters. You could move the hole all over but never get it stopped.

That's when I started calling people and no one would touch it. Being the nice guy I am, I was going to shoot it, but my brothers brother in law thought he and his buddies could fix it. So I gave it to them. That was about 1992. I was happy to see that pig gone. They fought it for a year or so. They gave up. In fact, they put the annular boosters back it.

It sat for six months or so, and then my brothers brother in law stuffed it up my buddy's butt. This time it was on a 440 in a B body with a automatic. The other cars were small block sticks.

Wasn't long before my buddy called and wanted me to fix it. I played with it a bit and figured why am I doing this? I already know it can't be fixed. So I had him call BLP, Chuck Nuytten and someone else. They all passed.

He sold the car but kept the carb; why I do not know.

In 1999 my cousin bought the car I now have. He didn't like the carb that was on it. And I couldn't get his cheap *** to buy from a pro. So my buddy shoved this carb right up my cousins butt, and he paid $275.00 for that hunk of crap. Since I did the tuning on the car, I was fighting the carb. Again.

The carb was just like herpes. Always shows up when you don't want it. And never goes away.

My cousin died in 2009 and I ended up with the car in 2013. So I bought a BLP billet base plate for it, and billet 5 emulsion metering blocks and converted the air bleeds so I can change them.

All for not. I went from 2 emulsion to 5 emulsion in sizes from .024-.035. Nothing. I drilled more air bleeds and emulsion jets than I care to remember. Didn't do a thing.

So I gave up and bought a BLP BX4. I can run a standard tune up. I can make a change and it actually changes.

So that is the short of it. I could have bought several carbs for the time and money wasted on that junker.

When I get some time, I'm taking that pig to the range. I'm going to unload on the crap my years of frustration. Then I'm going to leave it on the range to go back to the only time when that thing was any good. It's going back to its natural element.
 
After all that I would do the same thing, I'm sure you changed the PV's
If it had 2 if not I would have put one in the rear and modified the metering block to give it more fuel but it's odd because the problem with the annual booster is they are almost always rich on top. Pump cams, nozzles, PV's
can usually fix that problem, them modify the metering block last.
 
brian6pac said:
After all that I would do the same thing, I'm sure you changed the PV's
If it had 2 if not I would have put one in the rear and modified the metering block to give it more fuel but it's odd because the problem with the annual booster is they are almost always rich on top. Pump cams, nozzles, PV's
can usually fix that problem, them modify the metering block last.
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Did all that. And we tried 1:1 linkage. That actually made it tolerable.

For whatever reason that was one unhappy carb.
 
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