The Zenith type 228 was made in SEVERAL DIFFERENT flange sizes.

Start with the correct size, and no slotting is necessary; PLUS the internal venturi will be closer to being correct for your 261.

Jon.


Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop