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Discussion Starter #1
Have had this problem with my mid-production B since I got it, of the float not shutting off fuel flow, causing it to pour out of the air intake. Initially I simply cleaned up the needle valve and it was OK for quite awhile, but now it's back and I can't make it stop. I've checked out the float/needle valve operation and it works perfectly on the bench with the bottom of the bowl sealed and then filled with water. The float comes up and shuts the valve. I tightened up the pivot so there's no sideways slop in the float- I can't find that it's catching on anything. In researching, I found an answer that the bowl vent could be plugged, but on checking, it's a wide-open, clean passage from the base of the carb unit to a slot in front of the choke plate, so no issue there. Is it possible that my old float could somehow be underperforming in gasoline and not providing enough flotation? I've never had or heard of this problem, but I do note that the issue of this leakage seems to be common with these carbs.

'45 B, DLTX 34 carb
 

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Fuel pressure too high?
Needle not sealing against seat when float raised ?
Float not floating or binding?


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Discussion Starter #3
It's gravity-fed. I checked the float/needle/seat 6 ways from Sunday, made sure no slop, no binding. When I rotate the carb as little as 90 degrees it stops me from blowing air into the fuel inlet. This has to be something super simple. I flotation-tested the float, but I didn't keep it in water for any extended time. But, I've never noted it to have liquid in it on disassembling. Will now try immersing it for a time. Still, I would think it would have to have more than a slow leak to cause an immediate overflow.
 

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Floats have been known to rub against and hang up on the side of the carb bowl.
 

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Discussion Starter #6
There's plenty of crap that comes out of the old gas tank, but the sediment bowl catches that, plus there's a backup strainer at the carb fuel inlet, so I don't think it's that. And as I have said, I tightened up the float pivot, and there's no slop or offsetting.

OK, maybe this is it. I decided to re-examine the float. This time I shook it vigorously (don't know why I didn't before), and there's something going on in there. Enough to hear. Still it was far from completely swamped, and still floated easily. But I know this is no good, regardless. I submerged it in water for some hours to see if it would worsen, and it seemed to. Has to be a pinhole leak in the solder joint, not too bad to have made it this far, probably 75 years. I suppose I could attempt to resolder, but I just ordered a replacement.

Fingers crossed this is it!
 

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A gas tank cleaning needs to be on the "to do" list if it is full of junk.
 
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