Removed plug at bottom of glass filter bowl, will not drain.

[webcraft]

All new fuel and tank cleaned, but now I have brown gunge floating around in the bottom of the glass bowl.

Previously if this happened I unscrewed the plastic plug at the bottom of the bowl and any water and gunge came out. This time nothing much emerges, a tiny dribble then nothing, though the bowl is full.

I don't really want to dismantle the whole thing as I am in the middle of nowhere and last time I changed it it was very difficult to bleed the engine, but I had shore power then to charge the batteries. Currently at anchor in the wilderness with windless days fotecast and have to be back on Sunday.

If I just slacken the centre bolt a bit will this help the bowl to drain? Or do I have to bite the bullet and dismantle the thing?

 

[Poignard]

Have you tried poking a matchstick up through the drain hole?

 

[webcraft]

Have you tried poking a matchstick up through the drain hole?

I tried a small screwdriver. A match might be better, with the end frayed out a bit. Will try that tomorrow - dark now, dinner's on, enjoying a Talisker in the cockpit.

 

[stone beach]

If we are talking about a Racor, sounds like gunge is blocking the drain hole inside the plug / valve part. You can easily remove the plug / valve part with a spanner for a better clean of the glass bowl but be ready for the filter to empty entirely, not just the glass section.
Sometimes turning the valve backwards and forwards a few times (fully open to fully closed) will dislodge the gunge and clear it.
The hole turns through 90 deg so poking up the end may have limited success

 

[Poignard]

If we are talking about a Racor, sounds like gunge is blocking the drain hole inside the plug / valve part. You can easily remove the plug / valve part with a spanner for a better clean of the glass bowl but be ready for the filter to empty entirely, not just the glass section.
Sometimes turning the valve backwards and forwards a few times (fully open to fully closed) will dislodge the gunge and clear it.
The hole turns through 90 deg so poking up the end may have limited success

I think Webcraft has a CAV filter: "If I just slacken the centre bolt a bit will this help the bowl to drain? Or do I have to bite the bullet and dismantle the thing?"

 

[Daydream believer]

Undo the bleed screw to let air in the top

 

[Kwik Decision]

How full is your fuel tank? Depending on the location of the filter. it may be that when the tank is full there is enough head for the crud to easily flow out of the drain on the filter, but if the level is low, it won't.

 

[wiggy]

When you get time, I’d recommend fitting a priming bulb, like those used by outboard engines, right before your filter, that way bleeding is as simple as opening the bleed screw and pumping the bulb until no air is seen.

 

[Roberto]

CAV can have various types of draining bolts, one type has an outside vertical groove about half way along the thread, one unscrews the plug until the groove allows passage of liquid/gunge. Another type has a central hole in the plug part inside the bowl going to a hole perpendicular to the thread (much like a banjo bolt): if there is gunge this is likely to clog the 90° passage, one needs a flexible piece of wire to poke through the conduit, a wooden stick won't do.
If being careful, the central drain plug can often be totally unscrewed without dismantling the filter components (the central vertical axis keeping bowl-cartridge-head together will remain in place), you might pull the drain plug off, keep the filter closed with a finger the time to clean the drain plug, then put it back (do not close the tank tap or the filter will fill with air); the problem is the central axis is composed by several sections screwed together, one should only unscrew the drain bolt without risking to loosen all the rest.

 

[B27]

The glass bowl is the output side of a CAV filter, it should only have clean fuel and filtered water in it!

I'm sure some people connect them backwards though!

Gunge in the bowl suggests bug growing in the filter element?

 

[Metalicmike]

I have a small bottle of Diesel especially for this problem. When you open the valve your fuel is trying to get back to the tank so you have to let air in. I remove the top off the filter then drain off any water then top up with this small bottle that I have for said occasion.

 

[MontyMariner]

Undo the bleed screw to let air in the top

Yes, sounds like an airlock.

 

[webcraft]

When you get time, I’d recommend fitting a priming bulb, like those used by outboard engines, right before your filter, that way bleeding is as simple as opening the bleed screw and pumping the bulb until no air is seen.

That is getting done this Winter. Our other boat has one, and priming after a filter change is a five second job.

- W