Odd carb issue: any ideas/suggestions?

[GWGAllisfan]

I observed an odd thing happening with the carburetor on my B-212. Since I have just rebuilt the tractor, this weekend was the first time I have had it sitting with fuel in the tank for any time. Before this it had been run with a temporary tank that was removed. This weekend I had repaired the fuel fitting on the tank and put about a quart of fuel in the tank then ran it for 10-15 minutes to check it out. Everything ran fine. The odd thing is the next day as I walked by I smelled a light smell of gas. Since the tractor is sitting on cardboard, I looked to see if there was any dripping from the carburetor, but there was no spot on the floor, and the typical drop spot of the air cleaner hold down bolt was dry. The next day the smell was still there, but still dry under the tractor, no drips. What I did notice was that the carburetor body, under the float and about to the choke area, seemed to be wet. The tractor still started just fine, and ran normally, for as long as I felt safe running it in the garage area. I have considered the following causes for the observed effect: 1.) Perhaps a porous carb casting? I don’t exactly remember where this carb came from, but I do remember it got the overnight vinegar soak to remove the white crystals from the bowl. 2. Bowl gasket leak? I haven’t yet checked the four screws that hold it together. It could be just as simple as not enough gasket compression, but I’d expect a heavier leak than what I’m seeing if that was the case. 3. I doubt it’s an emulsion tube problem, since that usually creates a liquid leak, running down the floor of the carb. 3. Whatever it is, it seems to be more of a wicking than a leaking, so I’m a little unfamiliar with that, since usually you can find a drip point. Any ideas?

[MPH]

I did have one carb that the bowl was rotted out on and it leaked, but it actually had a hole through it. It's possible it could just be thin enough to 'soak' through. Shouldn't be gas sitting against the gasket on top the bowl if the the float is right, sounds like it is since it runs good.

[dentwizz]

I just went through that excersize with my 2010. After much analysis(months) and trial and error, I found the upper carb half was warped where the screws pulled down on it. I straightened them, then installed and it still did it(its actually quite flexible) so I ended up putting two gaskets on. Did the trick. No leakage now. To answer the question of porosity, the aluminum is in fact porous. Usually however, the gasoline will not soak through it unless there is a defect. When inspecting larger carbs like aircraft units, we use a dye that soaks into the defects and turns a certain color when reacted with another chemical.

[Bill4041]

you can try a thin coat of permatex on the sides of the bowl gasket, overtightening is not your freind, kinda common that these get warped i myself have done the 2 gasket trick, as long as its out put in a new needle and seat

[mendon-chalmers]

I had the same thing found the shut off under the tank was leaking thru the hollow part of the valve stem for some reason, it would not drip enough to wet under but I would feel gas at the bottom with my finger, tightening the nut didn't help at all, replaced shut off from sandy lake & is fine.