Still working with a refurb 111T. When it arrived, the burner was cocked at about a 35 deg. angle -- roughly at 10:00 as viewed from the front. Loosened the nut which holds the burner assembly to the tank, twisted the burner until it was a little past level in the other direction, and when I tightened the nut, it spun a little with it and was evened up nicely. But when I pump it up some and put it in water, I get bubbles from the nut. I have it as tight as I want to go. Do I need to treat the threads with some kind of plumbing gunk to get it to seal properly, or on the outside diameter of the fuel supply tube where it enters the tank, or what? This is a major fail and renders the unit useless until fixed -- I do not want to go up in a big fireball!
Brerarnold i have two 111's and when i stripped them down to fettle them and when i re assemmbled them i had to tighten the nut realy tight to stop it leaking. i state the obvious is the thread in sound condition or andy debris preventing a good. What i would do is empty the tank then pump a good amount of pressure in the tank and put some shaving foam or liquid soap around the nut and watch for bubbles and then very carefully tighten until the bubbles stop or take the burner out of the case and dip the pressurised tank in water watching for bubbles and then very carefully tighten the nut just a tweak at a time till the leak stops.
Has anyone ever tried using this stuff on the threads of burner fittings: Permatex® Aviation Form-A-Gasket® No. 3 Sealant Non-hardening liquid gasket sealant/dressing/coating is a thin, brushable dressing or sealer for close-fitting parts. Suitable for continuous temperatures to 400°F (204°C). Resistant to antifreeze, aviation fuels, high-detergent oils and lubricants. Conforms to MIL-S-45180 D, Type III. You can get it at most auto supply stores in the US and probably something similar is available in the rest of the world.
Thanks guys for the advice. I will keep what both of you said in mind. I had an idea in the meantime, and I wanted to share it before proceeding further. I keep a supply of lithium grease on hand for working with firearms. I put a thin coating on the threads over which the nut travels. I got the nut much tighter without feeling as though I was tightening too much, if that makes sense. I put some pressure on the (still empty) tank and immersed it again. No bubbles. 20 more strokes of the pump. No bubbles. 20 more strokes. No bubbles. And a final 20 strokes, still no bubbles. So it strikes me that I may have solved my problem. Perhaps tightening the nut more, as Mr. Optimus suggested, did the trick. Perhaps the grease added something to the equation also. I think I'm going to leave it at that for now, and not try to fire it up until some of you good folks have a chance to comment on this.
It's not the threads that seal the burner, its the bulbed end of the burner pipe (called an olive)that fits into the concave part of the tank exit. make sure that the olive and it's concave mating surface are clean and shiny and they should seal ok. Thread sealers or ptfe tape are only any use when there is a tapered thread like a 123 or a 210. Hope this helps Neil
