old briggs engine, carb inquiry

[bgsengine]

depends on the carb but that is the float bowl atmospheric vent - the one with the "brass insert" is just an orifice insert to reduce air flow (emissions limitations) not critical to your application unless it is completely blocked - in the other website's picture, you can see the port for that vent that should have air passing freely between the 2 holes - you will note that it lines up with a hole in the lower half that leads to the air intake (see the brass tube sticking out in picture # 23?) - that's why it is called an internally vented carburetor. - Also - if the float , needle and/or seat leaks, excess fuel that floods out will also go out that hole - which again results in fuel dripping from bottom of carburetor

[sgull]

You can use the edit function at Photobucket to shrink the pics. I do mine a 550 pixels.

I didn't know about that edit function before. Thanks bobudu.

Edit: I edited my earlier post now to include photos. shrunken at 550 pixels. thanks again

[sgull]

depends on the carb but that is the float bowl atmospheric vent - the one with the "brass insert" is just an orifice insert to reduce air flow (emissions limitations) not critical to your application unless it is completely blocked - in the other website's picture, you can see the port for that vent that should have air passing freely between the 2 holes - you will note that it lines up with a hole in the lower half that leads to the air intake (see the brass tube sticking out in picture # 23?) - that's why it is called an internally vented carburetor. - Also - if the float , needle and/or seat leaks, excess fuel that floods out will also go out that hole - which again results in fuel dripping from bottom of carburetor

Ah, thanks for the explanation. I'm pretty sure the passage down in my orifice is completely blocked. But it's not supposed to be, correct?

[bgsengine]

Yup - when the carb is all put together, blowing air through that tube in front of the choke should blow air into the carb bowl if it is blocked, the carb can vapor lock and won't feed fuel properly.

simple enough to test with a bit of tygon tubing attached to the vent in the carb throat and blow into it, with upper half removed, should have air blowing out the mating vent - then using the same tubing blow air into the vent where the "brass insert" appears (or in your case, does not exist and never did) and air should blow out the hole next to the carb venturi..

Or, just assemble the thing without a float and needle, run some gas into the fuel fitting on carb until it floods and see if fuel flows out the vent in front of the choke

[sgull]

I'm pretty sure the passage down in my orifice is completely blocked.

Turns out after double-checking, with some decent blowing (better than I did before), that the passage is not in fact blocked, at all.

blowing air through that tube in front of the choke should blow air into the carb bowl

Yup, it does indeed.

in the other website's picture, you can see the port for that vent that should have air passing freely between the 2 holes - you will note that it lines up with a hole in the lower half that leads to the air intake (see the brass tube sticking out in picture # 23?)

I see ^. However, my carb does not seem to include that brass tube sticking out. Maybe for the same type of reason as that missing "brass insert" I mentioned and your followup about it perhaps not being critical to my application? Hope so.

One other seemingly strange (to me) phenomenon is that upon close inspection I am noticing the float needle seat in my carb is completely missing. Pretty sure there should be a rubber material type seat there for the needle down there in that orifice, or at least some remnant if there ever was one, but no. No such seat.

[Deere2me]

I see ^. However, my carb does not seem to include that brass tube sticking out. Maybe for the same type of reason as that missing "brass insert" I mentioned and your followup about it perhaps not being critical to my application? Hope so.

One other seemingly strange (to me) phenomenon is that upon close inspection I am noticing the float needle seat in my carb is completely missing. Pretty sure there should be a rubber material type seat there for the needle down there in that orifice, or at least some remnant if there ever was one, but no. No such seat.

In your original post, the site you linked to CLEARLY shows/described the inlet needle seat! You need to get one, it should be in the rebuild kit. Not a phenomenon at all. I mean, ya got 8X10 COLOR glossy photos to help ya,no? Be sure to install it with the groove facing down!

EDIT/ADD: If yer carb has a rubber tipped inlet needle ( shouldn't), then ya don't need/use a rubber seat.

[sgull]

In your original post, the site you linked to CLEARLY shows/described the inlet needle seat! You need to get one, it should be in the rebuild kit. Not a phenomenon at all. I mean, ya got 8X10 COLOR glossy photos to help ya,no? Be sure to install it with the groove facing down!

Thanks, I suppose it should've been quite obvious to me that I clearly need to get one if it's not even there, and of course that such would be in the rebuild kit. I guess what I described as seeming to me like a strange phenomenon was that there was no old inlet needle seat still remaining down in the orifice. Perhaps it's not unheard of that those seats can just deteriorate completely? Just askin... not that it matters particularly what might've actually happened to the old one; the important fact is I need to get one as you say.

[sgull]

EDIT/ADD: If yer carb has a rubber tipped inlet needle ( shouldn't), then ya don't need/use a rubber seat.

Ah! Okay, well I just checked, and my inlet needle is indeed rubber tipped. So, apparently/obviously then I don't need no rubber seat after all. Whoa.

[Deere2me]

EDIT/ADD: If yer carb has a rubber tipped inlet needle ( shouldn't), then ya don't need/use a rubber seat.

Ah! Okay, well I just checked, and my inlet needle is indeed rubber tipped. So, apparently/obviously then I don't need no rubber seat after all. Whoa.

Yeah, I thought that might be the case, It's pretty unusual for the rubber seat to not be there! If ya overdo the blowgun, you can blow it out ( which is how I remove em'), and I have run across a couple that were all dried up. But the needle is the main clue.
You wanna replace the needle, even if it looks good, and be sure and do the ol' suck/blow before ya put it back together. The brass seat is replaceable if it leaks.

[sgull]

You wanna replace the needle, even if it looks good. The brass seat is replaceable if it leaks.

My rubber tipped needle does look good, actually. But best to go ahead anyway and replace my rubber tipped needle with the metal-tipped version with the new rubber seat seat that most typically comes with a rebuild kit?

If it turns out I discover my brass seat leaks (hope not) I'm not sure how to go about replacing it, but we'll cross that bridge when/if I come to it. Thanks