Slow down a minute guys. I have never seen a Walbro carb that had a pulse fitting on the SIDE of the carb. I think he is talking about the primer bulb fitting which of course, won't work. If his carb has a pulse fitting, it should look something like the second picture above; a fitting in the fuel pump cover, not the side of the carburetor.

Can you send us a picture of the carb?

Other than that, yes, you can drill and tap anywhere on the crankcase or back plate for a pressure pulse fitting. Pick a thicker part of the crankcase to do so, and of course make sure it won't hit/interfere with the crank, reed valve assembly, etc. I sometimes make a pulse hole in the base of the cylinder into a transfer port. Good thick location, and not in the way of anything usually.

Another option would be to just go ahead and drill the carb passage out and use the original Ryobi pulse hole...

And finally, as mentioned, the WT-340 carb is really too small. It has an 8mm venturi and the Ryobi will do best with an 11mm venturi. The size of the carb is determined by measuring the smallest diameter of the carb throat. Walbro carbs also have a number cast into them near the choke butterfly location. That number is the size of the venturi in 64's of an inch. For example a "28" would be 28/64" which equals .4375" which equals 11.1 mm, which is what you want.

AV8TOR