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post #1 of (permalink) Old 01-06-2003, 05:34 PM
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vacuum secondaries

Hey-

I've got an 84 351W in my CJ-5. It'a got the stock motorcraft (by Holley) carb, and the secondaries aren't hooked up. None of the little vacuum "trees" are still on the intake, so I need to know where to hook the secondaries up at, or which vacuum "tree" I need and where it goes.

Thanks-

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post #2 of (permalink) Old 01-06-2003, 06:24 PM
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Re: vacuum secondaries

You don't have to hook any vacuum lines up to get the secondaries to work. [img]images/graemlins/crazy.gif[/img]
What makes you think they're disconnected?
They won't operate without a load on the engine, if you're trying to get them to open while parked.

The only way to disconnect them, is to pull off the "c" clip at the base of the carb.
Check on the passenger side, aft of the choke.
You'll see a housing with 4 screws, triangular shaped in profile, with a rod coming out the bottom of it.
That rod attaches with the aforementioned "c" clip to the secondary throttle plates.
You may just have a leak in the diaphragm itself.
Not hard to replace, but IIRC, you'll need to pull off the choke to get the secondary vacuum diaphragm housing off.
This is what you should be looking for. (albeit, not a chrome one. [img]images/graemlins/wink.gif[/img])
Here's another shot of one with the "quick-change" conversion. (to change the secondary spring for different applications/performance)
At least you can now see the general area to check. [img]images/graemlins/grin.gif[/img]
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post #3 of (permalink) Old 01-06-2003, 11:14 PM
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Re: vacuum secondaries

WD-40

Thanks. I was under the impression that vacuum secondaries meant that they were hooked-up to vacuum via a vacuum line. How can I check to see if the secondaries are working? The only reason I suspected them of not working was that I thought they had to be hooked up somehow, and there is a place for hooking up a line of some sort sticking up between the choke and the triangular shaped housing.
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post #4 of (permalink) Old 01-07-2003, 01:51 PM
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Re: vacuum secondaries

there is a place for hooking up a line of some sort sticking up between the choke and the triangular shaped housing.
That vacuum fitting should be for the choke.
If you take a look at this picture, it should tell you where the vacuum hose goes for the choke.
The "open" 3/8" fitting is for the PCV valve, but I'm guessing your's is under the front of the carb.
I don't have any pics of the stock Ford/Holley here, but that linked one should be dang close.
If you're still running into problems, I'll see about getting you the Ford pic.

You can "manually" test your secondaries, but you'd be doing it "mechanically", not by vacuum.
Adjust the idle so it's around 1500rpm.
Locate the secondary actuation rod, and push up on it.
(That's the rod that comes out the bottom of the secondary diaphragm housing)
That will open the secondaries, and the engine will rev higher.
There's no other way to check, unless you disconnect that rod and verify the drop in performance on the road.
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post #5 of (permalink) Old 01-07-2003, 04:44 PM
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Re: vacuum secondaries

WD40-

Thanks for all the help. I'm going to look into hooking up the vacuum for the choke. The secondaries are fine it was just my misunderstanding of what "vacuum" secondaries meant. [img]images/graemlins/smirk.gif[/img]
post #6 of (permalink) Old 01-07-2003, 05:55 PM
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Re: vacuum secondaries

Cool! [img]images/graemlins/grin.gif[/img]
BTW, here's a great link for general information, and tuning for your carb.
Clicky here.

Chances are, if you didn't feel the secondaries kicking in, they're adjusted properly.
I.E. you've got the correct spring (for the diaphragm) for your application.
Another Cool! for ya!
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