The anti-siphon/vented-loop on my generator decides to leak at random. Quite
often it has no problems, but other times I'm seeing a trickle of water
running from it. The unit consists of a semi-circular stainless steel tube
with a plastic bulb on the top of it. When there's pressure the bulb seals
and when the pressure drops the bulb releases and breaks the siphon. I've
removed the bulb and checked it with mouth-pressure, and it seems fine.
There's no build-up on it.

I can't figure out what is causing this leak. The fact that it can come and
go during a single running session seems to indicate something other than a
particle/salt crystal/etc blocking it open. Are there any ideas as to what
might be causing this? Oh, the impeller on the water pump is new.

-- Geoff