'74 Toyota California Emissions


I’m in the process of swapping an aftermarket Weber carb onto this '74 Corolla I’m sort of sprucing up, but there is an extra hose going to the old carb that I don’t quite know what to do with.

I noticed a while ago that this is a California car (I’m not in CA). The only difference, as near as I can tell, is that it has this elaborate evaporative emissions control system that I don’t think still works. The tube in question is a 3/8 inch fuel line, but it goes to this box labeled “evaporative emissions control unit”, which in turn has a line that goes back into the firewall (presumably to the gas tank) and also has a bunch of little lines that are mostly capped off (by previous owner, I think), but are labeled to go the carb, the intake manifold and the distributor. There’s also a black cylinder that I presume to be the charcoal filter that has it’s own set of hoses and lines that goes back to the firewall.

So I figure this mystery hose is either supposed to vent the gas vapors from the tank into the carb or vent the vapors from the carb into the charcoal filter. If it’s the latter, I figure I can just cap it off, but if it’s the former, I don’t really want the fuel tank vapors being wafted into the engine compartment of just building up in the tank.

Anyone have ideas, insights or vaguely remembered recollections about these? Unfortunately, the manuals I have describe a slightly different tune-up procedure for CA models, but doesn’t mention the extra emissions equipment.