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How to Unclog The Air Tube Beyond The Checkvalve

Posted: Sat Jan 31, 2009 5:23 am
by Murff
From Frank Bebb-

Of course the problem is that tube at the end of the pump cylinder that runs to the top of the fount is plugged. I'm probably 6 out of 6 with this method and have recommended to others who were also successful:

1. Remove EVERYTHING from the fount, including the checkvalve.

2. Fill with fuel until full then install filler cap tightly.

3. Pour MORE fuel in through the valve hole at the top of the fount until full. This is part of the trick as the end of our blocked tube is very near the top of the fount, for safety reasons.

4. Gently re-install the valve, keeping as much fuel as you can inside the fount. Hand snugged is good.

5. Now we have to "gently" warm the fount. Summer in the southern California desert is usually perfect for heating a fount but winter is a bit more difficult. I DO NOT recommend you stick it in the oven! The idea is to raise the temperature a bit, which increases pressure, a bit. So safely figure a way to expose the fount to warming heat.

6. As the heat increases, so will internal pressure. After warming for an hour or two, take a look down the pump cylinder. If it is dry down there, you have longer to wait. If damp or if you can now see fuel, you're there or very close.

7. This may take a few hours, or a few days. My first took 3 days and I very nearly gave up on it. But if you keep the fuel under pressure it will, sooner or later, eat through the varnish block in the tube and clear it.