Uncooperative gascolator drain

[NM Doug]

We purchased our 9A already flying and just finished our first condition inspection. After buttoning everything back up, I took a turn around the pattern and returned to the shop to ask a few questions. We noticed there was a steady, relatively rapid drip from the gascolator fuel drain (Van's standard, the CAV-110).

The IA had removed the gascolator to inspect and clean the screen during the inspection. At this point, when we noticed the drip, he tried my fuel sampler a few times in the drain, and the dripping stopped. I flew back home.

Since this, I can only get a very very gradual sample from the gascolator drain, as if it's mostly clogged. I took another look this afternoon, and I see I could only change out the drain if the bottom cowl is off.

I don't know much about the functioning of the gascolator and how it interfaces with the drain, but I'm wondering if this can wait until the next oil change. If I am patient, I can still sample the drain for water (particularly if I start there and then move to sample the drains on the tanks). I welcome thoughts on whether this is OK for now.

Thanks,
Doug

[alpinelakespilot2000]

You have to turn your boost pump on when you check, otherwise you won't get much of anything.

Also, it might have been leaking because there was a piece of grit keeping it from closing completely or you might need a new o-ring. Or just buy a new valve from Van's.

Hope this helps.

[NM Doug]

Thanks - The drain works fine with the boost pump on as you suggested, and it isn't seeping or leaking. Before last week's condition inspection, I was able to sump fuel without the boost pump on - and so I simply had never tried with it on.

Doug

[DaAV8R]

I have read twice in recent weeks that the gascolator cannot be sumped without the boost pump turned on. Wouldn't the gascalator be full from the last engine run? I realize it coldn't be sumped over and over as the fuel tanks are lower than the gascolator. And what good would it do to sump the drain with the boost pump on? Wouldn't any water that came thru the gascolator already have collected in the bottom of the gascolator?

[JimWoo50]

I can't reach it on preflight anyway and had dripping issues so I plugged it. Now every time I have the cowl off I check it for water or accumulated crud. Never found anything yet 109 hrs checked it 4 times at least.

[Ron B.]

Maybe the fuel pump doesn't allow an easy free flow and a small vacuum is formed in the gascolator when being sampled?