[Spits] Fuel tank not breathing "out"

[Clark W. Nicholls]

This indicates that 
1) the funnel end is submerged below the level of fuel in the tank.
2) the funnel is sealing the tank and not allowing air to escape around it.
This causes the fuel to blow back when pressure builds.
3) the venting tube(s) to the canister are not open to bleed the pressure.

3) may be normal if there is a solenoid to shut off the venting with engine
off. The canisters probably vent to the carburetor.

You can check the vent tube by removing the outputs from the canisters and
blowing thru from the tank end. 
Then if all's clear, check the outputs.

Just food for thought...

Clark
Clark W. Nicholls
1972 Stag (LE7931E), 1974 Spitfire (FM14571U) 
and 1 rusty GT6 needing new owner
"Reality, it's not what you think."