Emulson tubes do suffer from errosion but more get wrecked from people shoviing stuff upthere insted of pulling them out to clean them.
Ditto for main jets they do not wear particularly fast .
The float amd float needle does wear both wear and should be considered a tune up item.
AKAIK there are no carb kits for Kawakasi engines .
They have not been in the big engine market for very long and "service kits" seem to be something they have not planned on.
So you will need a float, needle and seat ( if it is replaceable ) and a float bown gasket and while you are there, new manifold gaskes would not go astray.
But before you go buying parts it is usually a good idea to work out what is actually wrong.
SO if you have properly cleaned the float bowl, needle & seat, emulsion tube , idle circuit & bowl vent and it is still flooding the pull off the engine cover and check that the flywheel key is intact.
The 2 halves of the hole should make a perfect square, if not then pull the flywheel and replace the key.
You also need to check the cylinder compressions as a blown head gasket can also cause black fouled plugs.
Oil fouled plugs are wet, sort of shinny and feel greasy to the touch.
Carbon fouled plugs usually look dry and have a fluffy sooty deposit, even if the engine is flooding.
Fun comes when a flooding engine blows head gasket.
Next the valve lash need to be checked.
Kawakasi engines fail by bending and throwing push rods. they are designed to do that rather than blow up completely
Last test is to try and run the engne on one cylinder at a time.
With the carb off you can try a float test with a pressure pump or a spare tank held as high as possible above the carb to get a good head.
A float on a carb with an impule pump should hold 5 to 7 psi. if it has a electric or mechanical pump then it needs to hold 10 to 15 psi.
It helps a lot if you can remember exactly what happened before it started to play up.
It makes a difference when one starts to look.
Fo isntance if you were mowing heavy grass and it just stopped, or hit a rock / root/ branch then it started playing up or it was fine when you stopped mowing last season & just startedd playing up when you went to fire it up for this season.
There is always a reason why someting stops working properly.