What goes in this hole?

[dhughins]

My 84 has a old crate 350 with a Rochester 2jet. On this block off plate there is a hole causing a vacuum leak. What goes there or what can I put there? I hope you can see it well enough.

[v30crewcab]

that goes to the back of the carb right under the aircleaner on my motor.

[Skunksmash]

... I'll tell you when you're older

[dhughins]

Is there supposed to be some kind of fitting in it? I couldn't tell if the hole was threaded, it was getting dark. Will try to see tomorrow.

[SkinnyG]

It's just like the metal tube below it. It slips into the hole, but goes around to the back of the carb, and connects to a hole at the top edge of the air horn.

Inside that thingie is a tube that gets heat from the exhaust crossover. The choke housing has a wee bit of vacuum to it, which draws air through the whole thing - fresh air from the air horn, through the (missing) tube, into the hot cross over, and then into the choke housing.

Without it, the choke might never turn off.

[dhughins]

Thanks skinnyg. Would it be possible to get a picture of the line? Does it have fittings on both ends or what? This truck ran right the day I bought it drove it home then started having problems. I had a shop start to work on it and they didn't know what they were doing so I towed it home and have been fighting vacuum leaks ever since. I took Carb off and rebuilt, but never noticed that hole till I started messing with it over the weekend. Is there a fitting that goes in hole and then a rubber vacuum line from there?

[dhughins]

Went and looked in daylight. I see there are no threads. Looks like a fitting should be pressed in ?

[v30crewcab]

yep just presses in. not sure how tight, haven't taken one out.

[SkinnyG]

Mine is just as you see above.

The connecting hose at the air horn can be simple rubber. The connecting hose at the choke housing should be silicone so it doesn't melt (it's going to get very hot).

You should have a gasket for the bakelite choke cover, as well as a wee plastic double-spigot-spacer that connects between the choke housing and the carb body (the seal for the vacuum source).

Check all vacuum ports on the carb and make sure none of them are unplugged (don't forget the one at the back of the carb base for the hot air riser on the air filter).

Make sure the secondaries close all the way.

Make sure the primaries are as closed as you can get them (you don't have a rowdy cam, do you?).

When you assembled it, did you check for warpage at the air horn as well as the carb body? These are almost always warped by people over-tightening the carb bolts. Another potential source for leaks.

[Gotenntitans]

Originally Posted by Skunksmash

... I'll tell you when you're older

I knew when I saw the thread title someone was gonna getcha! GTT

[dfrank]

Throw it as far as you can and get a holley.

[SkinnyG]

Because of a missing hot-air choke tube? Interesting....

[Just call me Sean]

Well... I would ditch it for a Quadrajet with electric choke and stock type intake, but I see what he's getting at.

[dhughins]

Thanks for the answers and pictures that helps alot. now just gotta figure out a solution for it. I'm thinking I might be able to put a rubber vacuum fitting in there and run a line up to carb and see how it goes. the 1 on bottom in that picture has a piece coming out of plate that line goes in but the other 1 doesn't. I wonder why? you reckon just some 3/8 fuel line and bend it will sit down in there?

[SkinnyG]

No - don't use rubber at the heat-crossover plate, it gets too hot. Use metal.

If you cannot find the correct line at a wreckers, use a piece of metal fuel or brake line or whatever will fit snug. But metal. The metal line you are missing needs to be connected to the back of the carb air horn. This connection can be rubber (see top left of the picture).

An electric choke thingie would be the best fix, especially if you're running headers and/or have deleted the heat-riser valve in the passenger side exhaust manifold (this closes when cold, and forces passenger-side exhaust through the intake and out the driver's side).

[motornut]

closer to 1/4 tube inch i'd say
mines like that,when those screw up ,I tie off the choke till i can rule it out.
as the leak gets worse, so does the mileage

[dfrank]

Originally Posted by SkinnyG

Because of a missing hot-air choke tube? Interesting....

No, not because of a missing hot air choke tube, but because a holley is superior to a rochester 2 jet. Especially on a 350.

[buddy_1]

I found a good pic for you.
Look here for a universal repair kit. http://shop.advanceautoparts.com/p/d...ontent=5013143

[dhughins]

thanks buddy_1. the picture and link were both awesome. i ordered it from amazon for 5.99 should have it in a couple of days.

[buddy_1]

Glad I could help, Buddy

[Nin92]

Originally Posted by Skunksmash

... I'll tell you when you're older

Made me lol

[dhughins]

I got my hot air choke repair kit that's linked a couple post above. Can anyone tell me how to use it?

[y5mgisi]

Just FYI, those are super easy to convert to electric choke. Then you dont have to mess with the air tubes. Google something like "hot air quadrajet to electric choke".