Plugged Fuel Tank Fittings

I posted a version of this on the Defever owners forum but haven't heard back yet; I think it's general enough for this group.

There is a (female?) fitting near the bottom of each saddle fuel tank that has been plugged/glassed and possibly epoxied over by some PO. Not sure if this fitting arrangement is an original configuration . . . if it were, I suppose the lower fitting would be to allow any water and sludge thajt might be at the bottom of the the fuel to be drained off while the upper fitting allows clean fuel to be pulled from above during normal operations?

But why plug them? Looks like there were leaks in the past (or maybe stains while replacing or plugging the fittings). The cleaning service that inspected the tanks last year said they were in very good shape internally and did not notice anything amiss around these fitting on the inside but we didn't discuss them beyond that. Externally, the fittings feel very strong and I see no evidence of corrosion.

I'd much prefer to have working ball valves on the bottom fittings to tap water from the bottom of the tank, if that's their purpose, but I'm afraid to start pulling any of this material off the fittings until the tanks are completely drained (currently, there's only 25 gallons or so of fuel plus some powerful treatment in each tank).

So, is this a common configuration and am I correct about their purpose? Is the obvious solution the best--drain the tanks, cut away the plugs, inspect the fittings and replace them if necessary?

Thanks.

You could pump from on tank to the other. That would empty one tank and let you remove the plug if you wanted to and inspect/repair if necessary and replace with a drain valve.
While transferring the fuel you should probably run it thru a filter.

On my side tanks the fitting you have plugged is "open" to a ball valve then allowing gravity connection between tanks. I have never had the need to open the valves. The fuel pickups will empty the tanks to within two inches or so of the tank bottom.

I'd be careful monkeying around with that mess.

jleonard said:

You could pump from on tank to the other. That would empty one tank and let you remove the plug if you wanted to and inspect/repair if necessary and replace with a drain valve.
While transferring the fuel you should probably run it thru a filter.

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As configured, I can't pump below the level of the upper fitting, so there would still be several gallons of fuel behind the plugged lower fitting. (I guess I could pump from the filler port or inspection plate.)

sunchaser said:

On my side tanks the fitting you have plugged is "open" to a ball valve then allowing gravity connection between tanks. I have never had the need to open the valves. The fuel pickups will empty the tanks to within two inches or so of the tank bottom.

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Interesting. On my tanks, the upper of the two fittings pictured have that same feature. One of the PO's rigged them to move fuel from one tank to the other by gravity or to the transfer/polishing pump. It's that last two inches--where any water's likely to collect--that I'd like to be able to drain.

Capt.Bill11 said:

I'd be careful monkeying around with that mess.

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Exactly! Hence my post.

Some dumb surveyor in the past might have had a problem with a bottom drain in a fuel box. So it got plugged.

What size pipe fitting does it look like? I would carefully clean the head and exposed threads of the plug. If you decide after drainind the fuel down in the tank, that you don't feel comfortable trying to remove the plug, the other option would be to drill and tap it to a smaller pipe thread size. If it were a 1/2" plug, I might tap it 1/4". Certainly large enough for a water drain.

If it's a steel tank, I would remove the glass on and around the plug to make an accurate determination. Then I would likely try to remove the plug with modest effort. If it doesn't budge, either leave it alone or go to the above plan.

My boat's tanks came with drains valved and plugged. They are now the connection point for my fuel polisher / transfer pump. Very happy with this setup.

Ted

FF said:

Some dumb surveyor in the past might have had a problem with a bottom drain in a fuel box. So it got plugged.

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Actually, I hope this is the case since the fitting might be undamaged.

O C Diver said:

What size pipe fitting does it look like? I would carefully clean the head and exposed threads of the plug. If you decide after drainind the fuel down in the tank, that you don't feel comfortable trying to remove the plug, the other option would be to drill and tap it to a smaller pipe thread size. If it were a 1/2" plug, I might tap it 1/4". Certainly large enough for a water drain.

If it's a steel tank, I would remove the glass on and around the plug to make an accurate determination. Then I would likely try to remove the plug with modest effort. If it doesn't budge, either leave it alone or go to the above plan.

My boat's tanks came with drains valved and plugged. They are now the connection point for my fuel polisher / transfer pump. Very happy with this setup.

Ted

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Thanks for the ideas, Ted. Not sure of the size, but I suspect 1/2 inch. Wonder what the best way to remove fiberglass while not hurting the metal fitting would be . . . maybe a torch?

Just kidding .

Greetings,
Mr. 99. I've had success with delicate fiberglass alterations using a Dremel tool and a cutter attachment such as...
https://www.dremel.com/en-us/Access...es.aspx?catid=2070&catname=High+Speed+Cutters

angus99 said:

Thanks for the ideas, Ted. Not sure of the size, but I suspect 1/2 inch. Wonder what the best way to remove fiberglass while not hurting the metal fitting would be . . . maybe a torch?

Just kidding .

Click to expand...

Think I would start with a wire wheel on a drill. Should attack the glass without hurting the metal.

Ted

Perhaps there was a nipple and a fitting w a valve and someone kicked it off or something heavy fell on it so all the fuel in the tank drained into the bilge. If that had happened to a PO he'd be very likely to plug it. But w a male pipe thread hex head plug I would think.

Also perhaps a flush socket head plug was used and it leaked. Draining all the fuel in the tank could be viewed as an undesirable task so it got covered over w whatever like JB Weld. As suggested before I would'nt touch it unless it started to leak.