Weber 32/36 200 cold air intake. Vent back to carb. Jetting?

D

da66stang

Well-known member
[image]http://i.imgur.com/4pMY964.jpg[/image]

In the pic on the right hand side you can see a hose that comes out the front of the carb and heads back and up into the air cleaner. I assume it's some sort of fume vent that goes back into the system.

I left the cold air hat that I received today but don't recall seeing a spot for this vent. So what can I do to remedy the situation.

Thanks
 
When I had a weber 32/36 on mine, I had the exact same air cleaner you did. I simply blocked off that hole with a large nut/bolt and washer. The only lines I used for vacuum were for the PCV and the vacuum advance, neither of which would go to the air cleaner.
 
Holy cow that pic is huge. I swear it was smaller on my laptop.

Anyways from what I gather its a fuel bowl vent, any down sides to capping? I can't seem to find out what exactly it's purpose is other than it's supposed to be used with a canister which I don't have.
 
da66stang":w4qjoqgc said:
Holy cow that pic is huge. I swear it was smaller on my laptop.

Anyways from what I gather its a fuel bowl vent, any down sides to capping? I can't seem to find out what exactly it's purpose is other than it's supposed to be used with a canister which I don't have.
Click to expand...

Do not cap it, but you may be able to just leave it disconnected, or just drill a hole in your cold air carb hat and swap the bulkhead fitting from your current air cleaner over...
 
On my Weber, the bowl vents through those slotted openings just to the right of the choke plates - they open directly on the top of the bowl area.

I'd pull the hose off and blow into it. If air just comes out those slots, I'd cap it and be done. If not, then I'd pull the top of the carb and see where it goes internally.

I'm betting that it's 'supposed' to go to a charcoal canister, which would pull gas fumes out of the carb when sitting, then let them get sucked into the air cleaner (and burned) when running. If you don't have a canister, you don't need that vent line.
 
RichCreations":2d43yuim said:
da66stang":2d43yuim said:
Holy cow that pic is huge. I swear it was smaller on my laptop.

Anyways from what I gather its a fuel bowl vent, any down sides to capping? I can't seem to find out what exactly it's purpose is other than it's supposed to be used with a canister which I don't have.
Click to expand...

Do not cap it, but you may be able to just leave it disconnected, or just drill a hole in your cold air carb hat and swap the bulkhead fitting from your current air cleaner over...
Click to expand...


What makes you say this?
 
da66stang":2tuj1kse said:
RichCreations":2tuj1kse said:
da66stang":2tuj1kse said:
Holy cow that pic is huge. I swear it was smaller on my laptop.

Anyways from what I gather its a fuel bowl vent, any down sides to capping? I can't seem to find out what exactly it's purpose is other than it's supposed to be used with a canister which I don't have.
Click to expand...

Do not cap it, but you may be able to just leave it disconnected, or just drill a hole in your cold air carb hat and swap the bulkhead fitting from your current air cleaner over...
Click to expand...


What makes you say this?
Click to expand...
If it is the float bowl vent, you defiantly want it at "atmospheric pressure", otherwise how will the bowl "vent"? Plugging it is a good way to get "vapor lock" and such...
 
RichCreations":ds5ss3bk said:
If it is the float bowl vent, you defiantly want it at "atmospheric pressure", otherwise how will the bowl "vent"? Plugging it is a good way to get "vapor lock" and such...
Click to expand...

It also vents through the top, out the hholes to the right of the choke plates. From my readings it's used for a charcoal canister which I don't have.
 
If only my wife would tell me that more often.[/quote said:
:rolflmao:
(@ the expense of women) & (some guys)

Hey - the vent area mentioned here is what I believe is where the 'extra/overflow' goes. In the 4 WD world I believe we drill that out a few places b'cuz in off camber trail runs (side 2 side & frnt 2 back) the carb gets flooded or fuel starved if not modified this way...
Click to expand...
 
I installed the cold air intake and took the car for a spin. Sounds much better. The standard weber intake seemed to whistle from being so small. Could all be in my head. Anyways when I floor it now there seems to be a bit of a dead spot right at the beginning and then takes off.

Will getting more air from this intake cause the need to re-jet the carb? Still all new to this, used to a MAF adding more fuel on it's own.
 
If it was jetted with a really restrictive air filter, then yes going to a non-restrictive one would need re jetting.

However, sounds more like the accelerator pump, if it hesitates right when you mash the gas pedal but pulls well once it gets going.
 
jamyers":36rre3d2 said:
If it was jetted with a really restrictive air filter, then yes going to a non-restrictive one would need re jetting.

However, sounds more like the accelerator pump, if it hesitates right when you mash the gas pedal but pulls well once it gets going.
Click to expand...


Is there an adjustment for the pump? I checked some diagrams and see where it's locate but can't seem to find adjustment info. Possibly I googling the incorrect vocabulary.
 
Now that you ask and I think about it - I'm not sure.

There are difference pump nozzles, sized differently. Otherwise I don't recall an adjustment...odd.
 
I've always assumed the hole in the air cleaner baseplate was for the air inlet for the crankcase, to allow only filtered air into the crankcase.

I found out (the hard way) that you should keep the external bowl vent on the carb capped off. If you don't, the carb will run rich. The reason it happens is the air bleeds are pulling restricted air through the air filter, but the jets are not. Greater pressure in the fuel bowl than over the air bleeds causes a rich condition.
 
That float bowl vent can go to a canister or fuel return line. As for the accelerator pump, you may need to go to a bigger pump nozzle or dual pump nozzle. 0.50 single nozzle is stock, and they go up to 0.70. If I remember right, I have a dual outlet 0.70 on my 32/36 with synchronous linkage. I now have that on my 38/38.
 
The pump nozzle also has a blank port you can drill out with a micro drill bit. I wouldn't recommend doing that because its not as accurate as one that is already produced like that. I'll check my Weber carb book when I get home to see what they recommend.
 
da66stang":30cjumq9 said:
I installed the cold air intake and took the car for a spin. Sounds much better. The standard weber intake seemed to whistle from being so small. Could all be in my head. Anyways when I floor it now there seems to be a bit of a dead spot right at the beginning and then takes off.

Will getting more air from this intake cause the need to re-jet the carb? Still all new to this, used to a MAF adding more fuel on it's own.
Click to expand...

That whistling sound is characteristic of Webers (music to my ears) and only the volume changed when I changed air filters. I went to a cold air intake and I only needed to enrich the idle circuit rather than rejet. If you floor it and it hesitates, you're lean on the pump jet. Weber recommends a 0.65 pump jet as a starting point; I would imagine you want dual outlet, but the book doesn't specify. Hope this helps...
 
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