honda gx620 carb question

[gran_pann]

Hi everyone, I have a GX620K1 engine (QZB2, GCAD) the 2XXXXXX serial number

I have been trying to figure out what a certain hole in the carb is for and im stumped. I can see the fuel inlet, bowl drain outlet, and then there is this spot at the top that had some cut off hose running to it. I have searched the factory service manual, pictures online, users manual, and there really isnt anything I could find.

I can tell you that when I was cleaning the carb that this top hole goes to the top portion of the carb where the bowl area is (carb cleaner goes through it) but I am truly stumped.

Attached are some pictures of what I am talking about. Any ideas?

[ckau]

A vent to equalize air pressure in the float bowl. Most likely plumbed into the air box in stock configuration.

[gran_pann]

got it, thanks! Also, i am on the fence between a duster 94c and 100D CVT or a 780 drive/driven

any pros and cons to either?