Fuel pump T fitting

[YellowJacket RV9]

I am working on FWF connections, and am a bit confused as to how the KB-090-T fitting that attaches to output of the fuel pump works. The instructions indicate to screw it in until it is in the proper position, and then tighten the 'compression' nut. Looking at the fitting, however, I can't see how tightening that nut does anything. All it does is bear on a metal flange that doesn't budge; it doesn't compress the o-ring at all. If it tightened down onto a washer, that would make sense, but that flange is non-moving. Am I over-thinking this or is there something I am missing. This FWF is all new to me...

Thanks,

Chris

[grayforge]

I think the nut just tightens against the pump, binding the fitting into position. The o-ring seals just by simply sitting in its groove and pressing against the fitting and pump.

[TS Flightlines]

Chris---you are overthinking just a little----but good to ask!
Screw the fitting into the pump and index it where you want it, then tighten the lock nut to compress the O ring, and secure the fitting on the pump. Works well!
Tom

[YellowJacket RV9]

Thanks Tom!

Sometimes you just have to do something before it makes sense. I need to go spend a day with an A&P and pick his brain about engines...

Chris

[TS Flightlines]

Chris---no offense to the A&P's here, but if you want to learn about engines, go to an ENGINE Guy! Great A&P's arent necessarily great engine guys. Most are very well rounded in their line of work. Great movie quote,"you dont want to take the advise of someone that got a C- in astrophysics." That may or may not apply here. Many very good engine gurus on this forum, as well as in Florida.
Tom

[YellowJacket RV9]

Originally Posted by TS Flightlines

Chris---no offense to the A&P's here, but if you want to learn about engines, go to an ENGINE Guy! Great A&P's arent necessarily great engine guys. Most are very well rounded in their line of work. Great movie quote,"you dont want to take the advise of someone that got a C- in astrophysics." That may or may not apply here. Many very good engine gurus on this forum, as well as in Florida.
Tom

Good point. I know a great engine guy I had in mind. Thanks again; I may be calling you for a fuel line soon.

Chris

[Michael Burbidge]

Is there a suggested torque value for the nut?

[TS Flightlines]

I'll look it up, but getting a torque wrench in there is tough. FLats method, like AN fittings, works well.
Tom