No fuel flow from aftermarket fatbob

[HOOPLEHEAD]

Hello all,
I bought a basic type aftermarket fatbob from J&P. I prepped it with Kreem. I get good fuel flow from petcock. However, as soon as I connect a piece of hose, no matter the length, the flow stops immediately. Petcock was pretty inexpensive, but have used them before on a King Sportster tho with no problems.
I checked all bungs, fuel flows between tanks, doesn't make any difference if fuel caps are on or off tank. Doesn't matter if hose is 4", 6" or connected to my S&S carb. Tried everything I could think of.
Has anyone ever encountered this problem? Any suggestions? I am stumped.
Thanks,
Hooplehead

[1950Panhead]

Your hose is blocked, blow into the tank.

[HOOPLEHEAD]

Your hose is blocked, blow into the tank.

I examined every hose I tried. No blockage in any size or width fuel lines.
Boggles my mind.
Thanks for input

[panheadrider1961]

try a different pit cock maybe?

[Frankenstein]

It must be the petcock. I suspect the additional hose creates more suction by increasing the length of "fall" inside the line. I suspect there is an obstruction inside the petcock, imagine a thin flap of rubber hovering over the opening in the petcock. Greater flow pulls down the flap shutting off the flow. I imagine something like that is the problem. Might be able to take apart the petcock and clear the obstruction. It's a weird problem and I realize it's an off the wall possibilty, but worth a try.
DD

[HOOPLEHEAD]

try a different pit cock maybe?

I think that makes a lot of sense. I'm going to pick one up tomorrow. Geez, I've tried everything else...
I had a dumb attack, I should of thought of that. Dang it.
Thanks much!!
- Hoople

[HOOPLEHEAD]

It must be the petcock. I suspect the additional hose creates more suction by increasing the length of "fall" inside the line. I suspect there is an obstruction inside the petcock, imagine a thin flap of rubber hovering over the opening in the petcock. Greater flow pulls down the flap shutting off the flow. I imagine something like that is the problem. Might be able to take apart the petcock and clear the obstruction. It's a weird problem and I realize it's an off the wall possibilty, but worth a try.
DD

Thanks DD Frankenstein,
Excellent explanation and suggestion. Gotta be the petcock. Appreciate your taking the time to reply,
Thanks again,
-Hoople

[Buddhahoodvatoloco]

Frankenstein, admirable patience, and practical solution.

[HOOPLEHEAD]

Just to inform all; turned out to be bad petcock after all. Pan running great now. Glad I posted.
Thanks to all for your help!
- Hoople