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steve-wis

carb question on rebuild

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steve-wis
I am putting a kit in the carb off of a 5 3/4 hp briggs horizontal. The carb is apart but I have a question. Here are the pics.........








The top pic is the bottom half of the carb, the others are the top half. The question is this... the small hole I am pointing to with the pencil goes thru the top half of the carb on an angle, and the gasket has a hole in it to match it, but the bottom half doesn't seem to be drilled at all, just a shallow dimple there. Is the bottom hole supposed to go thru and I have a very plugged hole, or is it supposed to be only this shallow dimple? I picked at it and it seems to be metal. Anyone know what this does? Any help is appreciated. It is soaking right now and I will put it together tomorrow if I find out what to do with this hole. Thanks! Steve

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steve-wis
You are right again, Bob. After posting, I went back out and fished around some with a torch tip cleaner, and sure enough, there is a hole thru to the opening for the high jet. It is about .025" or so, by my guess. Got it cleaned out and it is soaking now, will put her together tomorrow and see what happens. Thanks Bob! Steve

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dynodave
That air path is called the air bleed. It goes to the emulsion tube/ jet and the air enters through the 2 or 4 little holes adjacent to the emusion tube seat (against the body). 1. It helps to percolate the fuel up the emulsion tube for delivery. 2. It also allows the main fuel jet design to have a much larger size, resulting in it's ability to pass a spec of dirt that would clog a much smaller jet in an unbled design (no one really uses an unbled design since antiquity) 3. It also prevents the over enrichment at higher engine speeds (air velocity through the venturi)

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steve-wis
Thanks for the info, Dave. I had taken this carb off a while back becuase the tractor wouldn't run right with it. Finally getting around to putting a kit in it, and found this hole to be blocked with the hard white scale that builds in a carb over time. Cleaned it out, put in new needle valves, emulsion tube, float valve and seat, and got it back on. Just mowed a bit of the yard with it and it is running pretty good. I do notice that when I hit a bump it likes to kind of die down for a second like it is starving for gas. I set the float to level like the instructions said, but thinking it may be a bit lean? Don't know what else would cause this. By the way, the engine is on a 575 stick steer Wonderboy. Thanks for all the info! Steve

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