fuel tank pressure

[PBH]

when refilling on a hot day recently I opened the fuel tank and there was a whoosh of air / vapour, should there be positive pressure in the tank or have I got a blocked vent. I did notice a petrol smell before opening the petrol cap. Is this pressure normal.

Thanks Peter

[wilf]

I don't believe so. You need to look at the tank vent system.

[Ian Durrant]

Wilf is right its not normal on a Stag.
I am surprised you haven't had carb flooding issues

[martin]

The tank vents through the petrol filter in the offside wing cavity, the filter only acts as a flame trap, but it, and the pipes must be clear. Martin.

[404ROD]

A friend of mine had to change the filler cap on his car - not a Stag - and got the wrong cap. What he got was one without a vent hole in it. The result was one concaved petrol tank. The non vented cap did not allow air to replace used petrol. Check the filter as Martin says. You remove the boot trim against the offside wing which exposes the filter and the fuel pump. The pipe goes through the floor so check that it has not been blocked by road dirt.