About 5years ago the fuel cap on my McCulloch Trim mac 250 started leaking
fuel through the vent hole in the cap for no apparent reason. I bought a
new cap and all was fine until today when I realised that fuel was dripping
out of the vent again.

There are no apparent cracks in the cap. The central vent €œplug€� looks to
be composed of partially fused metal beads. Any ideas why the vent is
failing like this? It just seems to €œhappen€� for no apparent reason.

Is there any way of restoring its fuel retaining properties whilst
retaining its air admittance properties? Its no big deal as replacement
caps are available on eBay but Im just curious as to how it works and why
it fails.

Tim

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Please don't feed the trolls