stunthanger.com
Engine basics => Engine set up tips => Topic started by: Jack Mulinix on April 17, 2010, 01:23:25 PM
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So, just went out to fire up new combo, an la25 with a brodak 3oz wide wedge, no muffler press. Filled the tank, couple rotations to get fuel, fired up no problem then fuel leaking everywhere. Seems to be flowing out overfill. First time with a real tank, always used clunks before. Do you need to cap them so no leak? Thanks in advance
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If it's a uniflow (three lines from the tank) then you should cap the overflow tube, but that's as much to make the uniflow work correctly as anything else.
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Not uniflo just standard
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Jack,
I sounds like the airflow over the open vents is creating a suction an pulling the fuel out. In the "bad" old days, we just cut off a piece of fuel tubing at a 45 degree angle and slipped it over the vents with the angle facing forward. Today, I plug the lower vent and route the upper vent to a piece of copper tubing bent 90 degrees to face into the airstream and located on the inboard side of the fuselage just above the top of the tank.
Steve
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On those old style stunt-vented tanks it's good to cap the top one and leave only the bottom open, especially for prolonged ground running.
Otherwise, all the fuel will be siphoned out the top vent.
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Thanks all. Will go and try again
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Went and tried again with top vent plugged and tried muff press. Much better but still not sweet. back to fiddling