With a little skill, you can make a 16 or 19mm Walbro pumper card fit where your Dell is. I put a 19mm HDA223B purge carb on my 50cc C1 Blata Clone Water cooled engine. It has 2 spring loaded screws on the side, keep a tiny screwdriver in your pocket for tuning, its a No Brainer. I have two real Dells, a 14/14mm SHA, 15mm PHBG piston carb., the latter is a nightmare. You have 2 jets, a pilot and main, mounted to 2 atomizer tubes, and then main and pilot jets, all of them have 100 choices, which do you use?? Its mind boggling, need a Carb tuner to keep it tuned, every 10 degrees to adjust the carb.
On mine you need a small screwdriver, lol.