fuel vent return from tank to canister

[YY1]

I'm getting a pressure buildup in the tank.

It's a new Canada made tank.

four vents to "manifold module" in front of tank.

I'm getting good vacuum from the carb to the charcoal canister.

I checked the line from the tank to the canister and it seems partially plugged.

I put a vacuum tester on it and can pump it up to about 30 inches, then it slowly bleeds down.

Is that normal?

Is there a common issue with anything in that system?

Have there been documented issues with those tank vents?

I suppose my next move is to test the line between the canister and the manifold, then the manifold separately.

Hoping to save a little time and a few busted knuckles dealing with that manifold.

Thanks much.

 

[idrivemopar]

The vapor separator in front of the tank may be corroded internally. since its a vapor separator, its possible for moisture to get inside. When I took mine off my 73 I soaked it in de-rusting solution, made sure I could hear the valve movement, and so far no problems. The other possibility as you mentioned is the line from the tank to the canister, could have enough corrosion to keep if from working normally. I would check the valve on the vapor separator is working correctly by disconnecting from the hard line to the canister at the vapor separator and do some vacuum tests on the seperator. There are no reproductions of this part, so cleaning is really the only option that I am aware of.

 

[YY1]

...and I just let a shell go that had one on it