Can anyone tell me from these pics?

 

Does it hiss when you take it off? If it does, its not venting.

 

It should be vented within a certain pressure or vacuum. Mine hisses a bit, but I have never had a fuel problem.

Cant tell from the pic. Are you having a low fuel pressure problem?

 

Thanks guys. I ask because I have a TINY weep out of the bottom of my 1904 carb. Only when sitting for more than a few hours to a couple days, it has been hot here and I was thinking that when it gets hot in my garage and the fuel expands, it is causing pressure to my carb and making the weep...does that make sense?

 

When I say bottom of carb, I mean the bottom where the bowl meets the body of carb

 

It should never leak, no matter the pressure (up to a certain point) If I remember, the cap is limited to 2psi max, & 3" of vacuum, since the fuel pump must be able to supply 4psi to the carb.

Even if the cap were plugged, the fuel pump should not be letting fuel get by it as well, otherwise the engine would fill up if parked on a hill.

 

I agree, it should never leak...I pulled out 2 other caps I have for truck and you can hear the ball in them when shaking, not the one pictured. I put the one that came on truck and will see what happens, either way I still need to straighten the body of carb where it meets bowl.

 

If you park the truck outside leave the cap off for a couple of days and see if the leak persists. Less than a great idea if the truck is garage-kept due to fumes.

 

1904's fuel bowls are notorious for leaking. Try bending the mounting tabs away from the carb. I've replaced gaskets at least 4x on my glass bowl carbs. I put thin coat of Permatex (fuel resistant 85420) on both sides of the gasket. Viola no leak.

 

how did you bend tabs? I would be afraid of breaking them...

video was posted in past of heating body of carb to straighten...but I have been avoiding because of having to tear apart carb and probably new rebuild kit.

 

Vice and a torch. Gotta do what ya gotta do. Take your time and pay attention.

https://www.youtube.com/watch?v=qgJvlKnoynw#t=12

 

oh yea, saw that-that is what I'm trying to avoid doing...but, may have to eventually do it

 

You will be glad you did. Buy a scrap carb and practice

 

as odd as it sounds I switched back to the vented, non locking cap that came with truck when I purchased and haven't had a single lil drop out of carb...coincidence?

now to get to all the little oil leaks...and sagging front drivers side...and kingpins...and...