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help with walbro carb

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Need help identifying a 1/4" hole I have on the front face of my Walbro carb. Do I plug it up or is it some form of air intake for the carb. I have some pics if you can see this hole. DA 1920 model# 1691020 with a 20hp Kohler engine. Any help greatly appreciated.









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I don't recall what carb I had, Kohler or Walbro, but here is a picture I had on my computer. Looking at the parts diagram, it looks like another screw to attach the intake elbow to the carb. It is a 10-32x2-1/4" long with a #10 flat washer according to the parts manual. The parts manual shows what looks like 3 screws to attach the elbow to the carb.



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To me it looks like the the 10/32 screw is turned into the carb. The hole i have in question is not threaded. Do i tap it and put a screw in? I have a parts diagram for this Walbro adjustable main jet, but I can not see this angle of the carb.

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That engine is old enough that if it should be threaded, plainly, it would have been. Does the hole go anywhere, or does it dead end? Stevenj has a good point, how is the intake elbow attached? Looks like there should be screws going down through a plate to attach the aircleaner base. If that hole is open, into the elbow, then there may have been a ball pressed in at one time. You may have to tear some of it apart to see if the hole passage lines up with the atmospheric vent on the carb. If so, it would remain open. Good Luck

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I think a ball may have been pressed in at one time due to the fact the area around the hole is clean while the rest of the surface area of elbow is blackened with years of dirt. The hole dead ends, no visible signs of attachment inside the bowl.

Thanks very much Steven and Stan for your information.

Do you think if that hole remains open it will suck in dusty air into the carb?

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If there is no passage up down or sideways, and the hole truly dead ends, it can't suck in anything so it is fine open.

If it is in fact the atmospheric vent, it still needs to be open.

It is very possible it is just a boss, built into the mold, to be used differently later in a different application, like a screw hole.

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