Carb Vapor Hose - 250 in a 1977

[D13]

1977 C10 w/250 1bbl. Emission label is long gone. Board members kindly provided me with emission hose diagram, when I hook it up everything seems fine. But...

The vapor port on the top of the carb, above the fuel bowl, which on most vehicles goes to the cannister, goes nowhere. There's not any type of plug or screen, it's just open to the air. There are no spare ports on the cannister or the intake, and the emission hose diagram I have does not show it connected.

I set my float too high on the rebuild and had gas pouring out it. I solved that by restting the float, but now I know there is a direct shot to thefuel bowl. Given driving in Michigan rain and snow, and dirt road dust in the summer, this doesn't seem very smart. I'm pretty sure that I can't just plug it, would seem to be the pressure vent for the fuel bowl.

Should I tee this into the big cannister line from the tank, just put a hose on it and let it dangle, or?

[beamn7]

Here is what I show in my 78 book... I'll go out tomorrow and look at my 78 250 (fed emissions) and let you know but I'm almost positive that it goes to the canister.

[D13]

My 77 doesen't have 5 connections at the can, I only have 3. That's what is puzzling me. The tother diagram I have shows the correct connections for the 3 port can but shows no connection for the carb.

Might be one of those things that looks wrong but is right.

[njlimbaugh]

I think you can plug the fitting to the float bowl. Enough air well get into the bowl through the accelerator pump shaft to prevent airlocks.