[BillB]

Is the carbon canister needed in the fuel system with a weber carb? (73 GT).

Car currently has electric fuel pump into fram fuel filter, primary line into carb, secondary running to fuel tank. The venting is connected similar to the fuel venting diagram (pdf by Charles Goin) with a couple variations. The current fuel tank is pre 73 (only one vent in rear of tank instead of two). The fuel filter line is T'd into the filler neck vent T, and the carbon canister line (carbon canister no longer exists). Otherwise the venting system is in accordance with the pdf diagrams. The carbon canister line is just hanging loose in the front end. Is the carbon cannister needed? Any recommendations on the open carbon canister vent line?

Thanks Bill

 

[madhatterpdc]

The carbon canister is a good way to control the venting to the fuel tank. Dangling like that, there is potential for the fuel tank to suck moisture in and contaminate the fuel. If capped, the fuel tank will go to vacuum and fight the suction of the fuel pump.

 

[GTJIM (R.I.P.)]

Venting!

The carbon canister is an essential part of the venting system AND for the control of fuel vapour emissions to atmosphere. Without one the venting system for carb and fuel tank is incomplete and moisture will make its way into the tank. PLUS - you are needlessly "grubbying up" the atmosphere, you polluter!

 

[kwilford]

Moved to the proper Forum...

Aside from the emissions and the risk (albeit slight) of drawing dirt and moisture into the gas tank, the main problem with having the tank vent line "just hanging loose in the front end" is that the fumes from the tank will be pouring out into the engine compartment. And unless it is dangling down low, into a slipstream of air as you drive, the fumes will likely find their way back into the cockpit.

The solution is pretty easy. Just find any similar-sized charcoal cannister from a car made in the late '70's to mid '80's carburetted car (maybe others as well, but I suspect that EFI cars used a somewhat different cannister design). Hook one port (it doesn't matter which) to the tank vent, and the other to a connection INSIDE the air filter housing (i.e. downstream of the filter). Have a look around this Forum, as I have posted photos showing one way to connect the cannister to a Weber.

HTH