Carb Help: "fuel bowl vent valve" on Motorcraft 2150

[Bilgamesh]

I have a situation in which cylinders 2,3,5 and 8 seem to be dead at idle. Since it is a dual plane intake, with each side of the carb serving 2 cylinders on each side of the engine, the symptoms have been attributed to one side of my 2 bbl carb not working, or an intake leak. I replaced the intake gaskets last night, and will put my orig. carb back on tonight to see if that fixes it. If not, as a backup plan I have bought a rebuilt Motorcraft 2150 carb. The new carb has a "fuel bowl vent valve" that my orig. does not have. It did not come with the linkage to actuate the valve, so I am assuming it is disabled without and will not affect the function of the carb, but I want to be sure it will not affect performance. My '74 Bronco has no emissions equipment cannister etc. I would appreciate any help or advice. - Thanks

 

[Bilgamesh]

I just spoke to my uncle who is an old-school Ford mechanic, used to work at Dub Richardson Ford in OKC. He said leaving the "Fuel bowl vent valve" without linkage and open will not affect the performance, but might piss off any environmentalist who looks under the hood.

 

[JoseyWales]

I'm trying to relieve some vaporlock issues on my engine. If I leave this bowl vent open, is it likely to spit out gas onto my engine when off road?

 

[DirtDonk]

I don't see any reason to leave it open. You've still got the two main vents into the float bowl. They stay under cover of the air-filter housing, so don't always pollute the air in your garage while parked.
The vent valve is for receiving vapors from the charcoal canister and should be able to be plugged without negative effect.

Paul

 

[DirtDonk]

I'm trying to relieve some vaporlock issues on my engine. If I leave this bowl vent open, is it likely to spit out gas onto my engine when off road?

I would say yes. So keep it either plugged or hooked to your charcoal canister. It's probably baffled by the bowl gasket, but that leaves it potentially open to overflow too. So yes, it could leak out on to your engine under the right (wrong?) circumstances.
Leaving it open should not help with a vapor lock issue, unless your main vents are plugged for some reason.

Paul

 

[JoseyWales]

Interesting. Thanks very much.