Does it look like this?This is a Zama carb,either came off of an echo or homlite weedie.Your engine in pic looks like an echo 24cc.Look for 3 triangles laying on there side that makes the shape of an E.look on base of cylinder and inside wall of the rear case.
number on mine is :K42K"---881or88i
Can you see any threads in hole or does it look like a piece of metal.My low is on left,high on right.Anyway,better just to get another carb.Get a walbro,heresa few numbers that have the same venturi.
WA167=====7.9 venturi------#20 stamped in intake maybe.
WA213=====7.9venturi--------- 20same as above
WT160B=====7.9 """""-----------""""""""""""""""""
I could give ya couple more with a bigger venturi but if its only a 21cc it wont take them anyway(like might not be a 24cc).