Leaky Needle on new style Magnum 15 XLS

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gsjames
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Joined: Wed Jul 11, 2007 10:26 am
Location: Weatherford, TX
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Leaky Needle on new style Magnum 15 XLS

Post by gsjames »

I bought 3 new blue-head Magnums 15's for this year. Two of them run just fine, but one of them kept going lean and "surging" after about 2 minutes of flying. It sounded like an air leak somewhere, so I re-plumbed the tank, checked all connections and tubing, etc, etc, but to no avail. I elevated the tank to ensure positive pressure, blah, blah, blah and STILL had the problem. FINALLY, yesterday at the field, still trying to figure out what the problem was, one of the guys suggested that it might be a leaky needle valve. The o-ring looked just fine and the needle wasn't loose in the spray bar, but I used the old fuel tubing trick and voila! the problem went away!

The moral of the story is that although I thought the new Magnum's had solved the leaky needle problems that plagued the older version, apparently they still are prone to leak air enough to cause problems. One of the guys in the club bought a bunch of o-rings and is going to give me a few replacements, but I think I'll put some tubing on the needles of the other engines just to be sure that I don't have any more problems.
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